Management

Manager and subadviser

Legg Mason Partners Fund Advisor, LLC (“LMPFA” or the “manager”), is the fund’s investment manager. LMPFA, with offices at 620 Eighth Avenue, New York, New York 10018, also serves as the investment manager of other Legg Mason-sponsored funds. LMPFA provides administrative and certain oversight services to the fund and manages the fund’s cash and short-term instruments. As of December 31, 2007, LMPFA’s total assets under management were approximately $193 billion. ClearBridge Advisors, LLC (“ClearBridge” or the “subadviser”) provides the day-to-day portfolio management of the fund.

ClearBridge has offices at 620 Eighth Avenue, New York, New York 10018 and is an investment adviser that was formed to succeed to the equity securities portfolio management business of Citigroup Asset Management (“CAM”), which was acquired by Legg Mason, Inc. (“Legg Mason”) in December 2005. As of December 31, 2007, ClearBridge’s total assets under management were approximately $100.5 billion.

LMPFA and ClearBridge are wholly-owned subsidiaries of Legg Mason. Legg Mason, whose principal executive offices are at 100 Light Street, Baltimore, Maryland 21202, is a global asset management company. As of December 31, 2007, Legg Mason had assets under management of approximately $998 billion.

Portfolio manager

Richard Freeman, investment officer of the subadviser, has been responsible for the day-to-day management of the fund’s portfolio since its inception in October 1983. Mr. Freeman has more than 34 years of securities business experience, 25 years of which has been with the subadviser or its predecessors.

The SAI provides information about the compensation of the portfolio manager, other accounts he manages, and any fund shares held by the portfolio manager.

Management fee

For the fiscal year ended August 31, 2007, the fund paid LMPFA a fee, after waivers and reimbursements, of 0.69% of the fund’s average daily net assets for investment management services.

A discussion regarding the basis for the Board’s approval of the fund’s current management agreement and sub-advisory agreement is available in the fund’s Semi-Annual Report for the period ended February 29, 2008.

Distribution plan

Legg Mason Investor Services, LLC (“LMIS” or the “distributor”), a wholly-owned broker/dealer subsidiary of Legg Mason, serves as the fund’s sole and exclusive distributor.

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Class IS shares are not subject to any distribution and/or service fees.

The distributor may make payments for distribution and/or shareholder servicing activities out of its past profits and other available sources. The distributor may also make payments to dealers for marketing, promotional or related expenses. The amount of these payments is determined by the distributor and may be substantial. The manager or an affiliate may make similar payments under similar arrangements.

The payments described in the paragraph above are often referred to as “revenue sharing payments.” The recipients of such payments may include the fund’s distributor, affiliates of the manager, broker/dealers, financial institutions and other financial intermediaries through which investors may purchase shares of the fund. In some circumstances, such payments may create an incentive for an intermediary or its employees or associated persons to recommend or sell shares of the fund to you. Please contact your financial intermediary for details about revenue sharing payments it may receive.

Recent developments

On May 31, 2005, the SEC issued an order in connection with the settlement of an administrative proceeding against Smith Barney Fund Management LLC (“SBFM”), the then-investment adviser or manager to the fund, and Citigroup Global Markets Inc (“CGMI”), a former distributor of the fund, relating to the appointment of an affiliated transfer agent for the Smith Barney family of mutual funds, including the fund (the “Affected Funds”).

The SEC order found that SBFM and CGMI willfully violated Section 206(1) of the Investment Advisers Act of 1940, as amended, and the rules promulgated thereunder (the “Advisers Act”). Specifically, the order found that SBFM and CGMI knowingly or recklessly failed to disclose to the boards of the Affected Funds in 1999 when proposing a new transfer agent arrangement with an affiliated transfer agent that: First Data Investors Services Group (“First Data”), the Affected Funds’ then-existing transfer agent, had offered to continue as transfer agent and do the same work for substantially less money than before; and that CAM, the Citigroup Inc. (“Citigroup”) business unit that, at the time, included the Affected Funds’ investment manager and other investment advisory companies, had entered into a side letter with First Data under which CAM agreed to recommend the appointment of First Data as sub-transfer agent to the affiliated transfer agent in exchange for, among other things, a guarantee by First Data of specified amounts of asset management and investment banking fees to CAM and CGMI. The order also found that SBFM and CGMI willfully violated Section 206(2) of the Advisers Act by virtue of the omissions discussed above and other misrepresentations and omissions in the materials provided to the Affected Funds’ boards, including the failure to make clear that the affiliated transfer agent would earn a high profit for performing limited

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functions while First Data continued to perform almost all of the transfer agent functions, and the suggestion that the proposed arrangement was in the Affected Funds’ best interests and that no viable alternatives existed.

SBFM and CGMI do not admit or deny any wrongdoing or liability. The settlement does not establish wrongdoing or liability for purposes of any other proceeding. The SEC censured SBFM and CGMI and ordered them to cease and desist from violations of Sections 206(1) and 206(2) of the Advisers Act. The order required Citigroup to pay $208.1 million, including $109 million in disgorgement of profits, $19.1 million in interest, and a civil money penalty of $80 million. Approximately $24.4 million has already been paid to the Affected Funds, primarily through fee waivers. The remaining $183.7 million, including the penalty, has been paid to the U.S. Treasury and will be distributed pursuant to a plan submitted for the approval of the SEC. At this time, there is no certainty as to how the above-described proceeds of the settlement will be distributed, to whom such distributions will be made, the methodology by which such distributions will be allocated, and when such distributions will be made. The order also required that transfer agency fees received from the Affected Funds since December 1, 2004, less certain expenses, be placed in escrow and provided that a portion of such fees might be subsequently distributed in accordance with the terms of the order. On April 3, 2006, an aggregate amount of approximately $9 million held in escrow was distributed to the Affected Funds.

The order required SBFM to recommend a new transfer agent contract to the Affected Funds’ boards within 180 days of the entry of the order; if a Citigroup affiliate submitted a proposal to serve as transfer agent or sub-transfer agent, SBFM and CGMI would have been required, at their expense, to engage an independent monitor to oversee a competitive bidding process. On November 21, 2005, and within the specified timeframe, the Affected Funds’ boards selected a new transfer agent for the Affected Funds. No Citigroup affiliate submitted a proposal to serve as transfer agent. Under the order, SBFM also must comply with an amended version of a vendor policy that Citigroup instituted in August 2004.

Although there can be no assurance, the manager does not believe that this matter will have a material adverse effect on the Affected Funds.

On December 1, 2005, Citigroup completed the sale of substantially all of its global asset management business, including SBFM, to Legg Mason.

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Retirement and institutional investors —Eligible investors

Class IS shares may be purchased only by Retirement Plans with omnibus accounts held on the books of the fund and Institutional Investors. In order to purchase Class IS shares, an investor must hold its shares in one account with the fund.

“Retirement Plans” include 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit-sharing plans, non-qualified deferred compensation plans and other similar employer-sponsored retirement plans. Retirement Plans do not include individual retirement vehicles, such as traditional and Roth individual retirement accounts, Coverdell education savings accounts, individual 403(b)(7) custodial accounts, Keogh plans, SEPs, SARSEPs, SIMPLE IRAs, or Section 529 savings accounts. Although Retirement Plans with omnibus accounts held on the books of the fund are not subject to minimum initial or subsequent investment requirements for Class IS shares, certain investment minimums may be imposed by a financial intermediary.

“Institutional Investors” generally include corporations, banks, trust companies, insurance companies, investment companies, foundations, endowments, defined benefit plans and other similar entities. Institutional Investors may invest in Class IS shares if they meet the $1,000,000 minimum initial investment requirement. There is no minimum subsequent investment requirement for Institutional Investors.

In order to purchase Class IS shares, an investor must hold its shares in one account with the fund.

Plan sponsors, plan fiduciaries and other financial intermediaries may choose to impose qualification requirements for plans that differ from the fund’s share class eligibility standards. In certain cases this could result in the selection of a share class with higher service and distribution related fees than otherwise would have been charged. The fund is not responsible for, and has no control over, the decision of any plan sponsor, plan fiduciary or financial intermediary to impose such differing requirements. Please consult with your plan sponsor, plan fiduciary or financial intermediary for more information about available share classes.

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Buying shares

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Other things to know about transactions

When you buy, exchange or redeem shares, your request must be in good order. This means you have provided the following information, without which your request may not be processed:

The fund’s transfer agent or Legg Mason Partners Shareholder Services will employ reasonable procedures to confirm that any telephone exchange or redemption request is genuine, which may include recording calls, asking the caller to provide certain personal identification information, sending you a written confirmation or requiring other confirmation procedures from time to time. If these procedures are followed, neither the fund nor its agents will bear any liability for such transactions.

Signature guarantees

To be in good order, your redemption request must include a signature guarantee if you:

You can obtain a signature guarantee from most banks, dealers, brokers, credit unions and federal savings and loan institutions, but not from a notary public.

The fund has the right to:

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Small account balances/Mandatory redemptions

If at any time the aggregate value of the fund shares in your account is less than $500 for any reason (including solely due to declines in net asset value and/or failure to invest at least $500 within a reasonable period), the fund reserves the right to ask you to bring your account up to the applicable minimum investment amount as determined by your Service Agent. In such case you shall be notified in writing and will have 60 days to make an additional investment to bring your account value up to the required level. If you choose not to do so within this 60-day period, the fund may close your account and send you the redemption proceeds. In the event your account is closed due to a failure to increase your balance to the minimum required amount, you will not be eligible to have your account subsequently reinstated without imposition of any sales charges that may apply to your new purchase. The fund may, with prior notice, change the minimum size of accounts subject to mandatory redemption, which may vary by class, or implement fees for small accounts.

Subject to applicable law, the fund may, with prior notice, adopt other policies from time to time requiring mandatory redemption of shares in certain circumstances.

For more information, please contact your Service Agent or Legg Mason Partners Shareholder Services or consult the SAI.

Frequent purchases and redemptions of fund shares

Frequent purchases and redemptions of fund shares may interfere with the efficient management of the fund’s portfolio by its portfolio manager, increase portfolio transaction costs, and have a negative effect on the fund’s long-term shareholders. For example, in order to handle large flows of cash into and out of the fund, the portfolio manager may need to allocate more assets to cash or other short-term investments or sell securities, rather than maintaining full investment in securities selected to achieve the fund’s investment objective. Frequent trading may cause the fund to sell securities at less favorable prices. Transaction costs, such as brokerage commissions and market spreads, can detract from the fund’s performance. In addition, the return received by long-term shareholders may be reduced when trades by other shareholders are made in an effort to take advantage of certain pricing discrepancies, when, for example, it is believed that the fund’s share price, which is determined at the close of the NYSE on each trading day, does not accurately reflect the value of

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the fund’s portfolio securities. Funds investing in foreign securities have been particularly susceptible to this form of arbitrage, but other funds could also be affected.

Because of the potential harm to funds in the Legg Mason Partners funds complex and their long-term shareholders, the Board of the fund has approved policies and procedures that are intended to discourage and prevent excessive trading and market timing abuses through the use of various surveillance techniques. Under these policies and procedures, the fund may limit additional exchanges or purchases of fund shares by shareholders who are believed by the manager to be engaged in these abusive trading activities in the fund or in other funds within the fund complex. In the event that an exchange request is rejected, the shareholder may nonetheless redeem its shares. The intent of the policies and procedures is not to inhibit legitimate strategies, such as asset allocation, dollar cost averaging, or similar activities that may nonetheless result in frequent trading of fund shares.

Under the fund’s policies and procedures, the fund reserves the right to restrict or reject purchases of shares (including exchanges) without prior notice whenever a pattern of excessive trading by a shareholder is detected within the fund complex. A committee established by the manager administers the policy. The policy provides that the committee will use its best efforts to restrict a shareholder’s trading privileges in the Legg Mason Partners funds if that shareholder has engaged in a total of four or more “Round Trips” (as defined below) across all Legg Mason Partners funds during any rolling 12-month period. However, the committee has the discretion to determine that restricting a shareholder’s trading privileges is not necessary (or that a new limit on Round Trips should be established for the shareholder) if it is determined that the pattern of trading is not abusive or harmful. In making such a determination, the committee will consider, among other things, the nature of the shareholder’s account, the reason for the frequent trading, the amount of trading and the particular funds in which the trading has occurred. Additionally, the committee has the discretion to make inquiries or to take action against any shareholder whose trading appears inconsistent with the frequent trading policy. Examples of the types of actions the committee may take to deter excessive trading in a shareholder account include restricting the shareholder from purchasing additional shares in a fund altogether or imposing other restrictions (such as requiring purchase orders to be submitted by mail) that would deter the shareholder from trading frequently in the funds.

A “Round Trip” is defined as a purchase (including subscriptions and exchanges) into a fund followed by a sale (including redemptions and exchanges) of the same or a similar number of shares out of the fund within 30 days of such purchase. Purchases and sales of the fund’s shares pursuant to an automatic investment plan or similar program for periodic transactions are

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not considered in determining Round Trips. For purposes of these policies and procedures, the Legg Mason Partners funds complex also includes certain Western Asset funds and Barrett Opportunity Fund, Inc., but does not include money market funds in the fund complex.

The policies apply to any account, whether an individual account, accounts with financial intermediaries such as investment advisers, broker/dealers or retirement plan administrators, commonly called omnibus accounts, where the intermediary holds fund shares for a number of its customers in one account. The fund’s ability to monitor trading in omnibus accounts may, however, be severely limited due to the lack of access to an individual investor’s trading activity when orders are placed through these types of accounts. There may also be operational and technological limitations on the ability of the fund’s service providers to identify or terminate frequent trading activity within the various types of omnibus accounts. The fund’s distributor has entered into agreements with intermediaries requiring the intermediaries to, among other things, help identify frequent trading activity and to prohibit further purchases or exchanges by a shareholder identified as having engaged in frequent trading. These agreements took effect on October 16, 2007.

The fund’s policies also require personnel such as portfolio managers and investment staff to report any abnormal or otherwise suspicious investment activity, and prohibits short-term trades by such personnel for their own account in mutual funds managed by the manager and its affiliates, other than money market funds. The fund has also adopted policies and procedures to prevent the selective release of information about the fund’s portfolio holdings, as such information may be used for market-timing and similar abusive practices.

The fund’s policies provide for ongoing assessment of the effectiveness of current policies and surveillance tools, and the Board reserves the right to modify these or adopt additional policies and restrictions in the future. Shareholders should be aware, however, that any surveillance techniques currently employed by the fund or other techniques that may be adopted in the future may not be effective, particularly where the trading takes place through certain types of omnibus accounts. As noted above, if the fund is unable to detect and deter trading abuses, the fund’s performance, and its long-term shareholders, may be harmed. In addition, shareholders may be harmed by the extra costs and portfolio management inefficiencies that result from frequent trading of fund shares, even when the trading is not for abusive purposes. Furthermore, the fund may not apply its policies consistently or uniformly, resulting in the risk that some shareholders may be able to engage in frequent trading while others will bear the costs and effects of that trading. The fund will provide advance notice to shareholders and prospective investors of any specific restrictions on the trading of fund shares that the Board may adopt in the future.

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Share certificates

The fund does not issue share certificates.

Record ownership

If you hold shares through a Service Agent, your Service Agent may establish and maintain your account and be the shareholder of record. In the event that the fund holds a shareholder meeting, your Service Agent, as record holder, will vote your shares in accordance with your instructions. If you do not give your Service Agent voting instructions, your Service Agent may nonetheless, under certain circumstances, be entitled to vote your shares.

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Dividends, distributions and taxes

Dividends and distributions

The fund generally pays dividends and makes capital gain distributions, if any, typically once or twice a year. The fund may pay additional distributions and dividends at other times if necessary for the fund to avoid a federal tax. The fund expects distributions to be primarily from capital gains. Capital gain distributions and dividends are reinvested in additional fund shares of the same class you hold. You do not pay a sales charge on reinvested distributions or dividends. Alternatively, you can instruct your Service Agent or Legg Mason Partners Shareholder Services to have your distributions and/or dividends paid in cash. You can change your choice at any time to be effective as of the next distribution or dividend.

Taxes

In general, redeeming shares, exchanging shares and receiving dividends and distributions (whether in cash or additional shares) are all taxable events. The following table summarizes the tax status to you of certain transactions related to the fund.

Distributions attributable to short-term capital gains are treated as dividends, taxable as ordinary income. Taxable dividends and long-term capital gain distributions are taxable whether received in cash or reinvested in fund shares. Although dividends (including dividends from short-term capital gains) are generally taxable as ordinary income for taxable years beginning before January 1, 2011, individual shareholders who satisfy certain holding period and other requirements are taxed on such dividends at long-term capital gain rates to the extent the dividends are attributable to “qualified dividend income” received by the fund. “Qualified dividend income” generally consists of dividends received from U.S. corporations (other than dividends from tax-exempt organizations and certain dividends from real estate investment trusts and regulated investment companies) and certain foreign corporations. Long-term capital gain distributions are taxable to you as long-term capital gain regardless of how long you have owned your shares. You may want to avoid buying shares when the fund is about to declare a long-term capital gain distribution or a dividend because it will be taxable to you even though it may actually be a return of a portion of your investment.

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A dividend declared by the fund in October, November or December and paid during January of the following year will, in certain circumstances, be treated as paid in December for tax purposes.

After the end of each year, your Service Agent or the fund will provide you with information about the distributions and dividends you received and any redemptions of shares during the previous year. If you do not provide the fund with your correct taxpayer identification number and any required certifications, you may be subject to back-up withholding on your distributions, dividends and redemption proceeds. Because each shareholder’s circumstances are different and special tax rules may apply, you should consult your tax adviser about your investment in the fund.

The above discussion is applicable to shareholders who are U.S. persons. If you are a non-U.S. person, please consult your own tax adviser with respect to the U.S. tax consequences to you of an investment in the fund.

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Share price

You may buy, exchange or redeem shares at their net asset value next determined after receipt of your request in good order, plus any applicable sales charge. The fund’s net asset value per share is the value of its assets minus its liabilities divided by the number of shares outstanding. Net asset value is calculated separately for each class of shares. The fund calculates its net asset value every day the NYSE is open. This calculation is done when regular trading closes on the NYSE (normally 4:00 p.m., Eastern time). The NYSE is closed on certain holidays listed in the SAI.

The Board has approved procedures to be used to value the fund’s securities for the purposes of determining the fund’s net asset value. The valuation of the securities of the fund is determined in good faith by or under the direction of the Board. The Board has delegated certain valuation functions for the fund to the manager.

The fund generally values its securities based on market prices determined at the close of regular trading on the NYSE. The fund’s currency valuations, if any, are done as of when the London Stock Exchange closes, which is usually at 12 noon Eastern time, as the manager believes that these valuations typically reflect the largest trading volume in the foreign currency markets. A material change in the value of currency during the period between the close of the London Stock Exchange and the calculation of the fund’s net asset value on the same date is considered a significant event, as described below, in response to which the fund may use fair valuation procedures to value the affected investments. For equity securities that are traded on an exchange, the market price is usually the closing sale or official closing price on that exchange. In the case of securities not traded on an exchange, or if such closing prices are not otherwise available, the market price is typically determined by independent third party pricing vendors approved by the fund’s Board using a variety of pricing techniques and methodologies. Short-term debt obligations that will mature in 60 days or less are valued at amortized cost, unless it is determined that using this method would not reflect an investment’s fair value. If vendors are unable to supply a price, or if the price supplied is deemed by the manager to be unreliable, the market price may be determined using quotations received from one or more broker/dealers that make a market in the security. When such prices or quotations are not available, or when the manager believes that they are unreliable, the manager may price securities using fair value procedures approved by the Board. Because the fund may invest in securities of small capitalization companies — some of which may be thinly traded, for which market quotations may not be readily available or may be unreliable — the fund may use fair valuation procedures more frequently than funds that invest primarily in securities that are more liquid, such as securities of large capitalization domestic issuers. The fund may also use fair value procedures if the manager determines that a significant event has occurred between the time at which a market price is determined and the time at which

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the fund’s net asset value is calculated. In particular, the value of foreign securities may be materially affected by events occurring after the close of the market on which they are valued, but before the fund prices its shares. The fund uses a fair value model developed by an independent third party pricing service to price foreign equity securities on days when there is a certain percentage change in the value of a domestic equity security index, as such percentage may be determined by the manager from time to time.

Valuing securities at fair value involves greater reliance on judgment than valuation of securities based on readily available market quotations. A fund that uses fair value to price securities may value those securities higher or lower than another fund using market quotations or its own fair value methodologies to price the same securities. There can be no assurance that the fund could obtain the fair value assigned to a security if it were to sell the security at approximately the time at which the fund determines its net asset value.

The fund may invest in securities that are listed on foreign exchanges that trade on weekends and other days when the fund does not price its shares. Therefore, the value of the fund’s shares may change on days when you will not be able to purchase or redeem the fund’s shares.

In order to buy, redeem or exchange shares at that day’s price, you must place your order with your Service Agent or the transfer agent before the NYSE closes. If the NYSE closes early, you must place your order prior to the actual closing time.

It is the responsibility of the Service Agents to transmit all orders to buy, exchange or redeem shares to the transfer agent on a timely basis.

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Financial highlights

The financial highlights tables are intended to help you understand the performance of Class A shares for the past five years. Class IS and Class A are invested in the same portfolio of securities. No financial highlights are presented for Class IS shares as the fund commenced the offering of such shares as of the date of this Prospectus. The returns for Class IS shares will differ from those of Class A to the extent that their expenses differ. Certain information reflects financial results for a single share. Total return represents the rate that a shareholder would have earned (or lost) on a fund share assuming reinvestment of all dividends and distributions. The information in the following tables has been derived from the fund’s and the predecessor fund’s financial statements. Except for the financial highlights for the six months ended February 28, 2008, which are unaudited, these financial statements have been audited by            , independent registered public accounting firm, whose report, along with the fund’s financial statements, is included in the annual report (available upon request). The financial information shown below for the periods prior to April 16, 2007 is that of the fund’s predecessor.

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Legg Mason Partners Funds Privacy Policy

[This page is not part of the prospectus.]

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Legg Mason Partners Aggressive Growth Fund

(Investment Company Act

file no. 811-06444)

FD01060 07/08

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PROSPECTUS / JULY     , 2008

Legg Mason Partners

Fundamental Value Fund

Class IS Shares

The Securities and Exchange Commission has not approved or disapproved these securities or determined whether this Prospectus is accurate or complete. Any statement to the contrary is a crime.

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This Prospectus offers Class IS shares of the fund. Class IS shares are sold with no front-end sales charge or contingent deferred sales charge only to Retirement Plans with omnibus accounts held on the books of the fund and Institutional Investors. See “Retirement and institutional investors” for additional information.

As part of a number of initiatives launched in 2006 to restructure and streamline the Legg Mason Partners fund complex, the fund assumed the assets and liabilities of a predecessor fund with the same name, effective April 16, 2007. Any information in this Prospectus relating to the fund prior to April 16, 2007 relates to the fund’s predecessor.

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Investments, risks and performance

Investment objective

The fund seeks long-term capital growth. Current income is a secondary consideration.

Principal investment strategies

Key investments

The fund invests primarily in common stocks and common stock equivalents, such as preferred stocks and securities convertible into common stocks, of companies the portfolio managers believe are undervalued in the marketplace. While the portfolio managers select investments primarily for their capital appreciation potential, secondary consideration is given to a company’s dividend record and the potential for an improved dividend return. The fund invests in securities of large, well-known companies but may also invest a significant portion of its assets in securities of small to medium sized companies when the portfolio managers believe smaller companies offer more attractive value opportunities.

Foreign investments

The fund may invest up to 25% of its assets in securities of foreign issuers which may involve greater risk than securities of U.S. issuers. Many foreign countries the fund may invest in have markets that are less liquid and more volatile than markets in the United States. In some foreign countries, less information is available about foreign issuers and markets because of less rigorous accounting and regulatory standards than in the United States. Currency fluctuations could erase investment gains or add to investment losses. The risks of investing in foreign securities are greater for securities of emerging market issuers because political or economic instability, lack of market liquidity, and negative government actions, such as currency controls or seizure of private businesses or property, are more likely.

Selection process

The portfolio managers employ a two-step stock selection process in their search for undervalued stocks of temporarily out of favor companies. First, the portfolio managers use proprietary models and fundamental research to try to identify stocks that are underpriced in the market relative to their fundamental value. Next, the portfolio managers look for a positive catalyst in the company’s near term outlook which the portfolio managers believe will accelerate earnings or improve the value of the company’s assets. The portfolio managers also emphasize companies in those sectors of the economy which the portfolio managers believe are undervalued relative to other sectors.

When evaluating an individual stock, the portfolio managers look for:

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Principal risks of investing in the fund

Investors could lose money on their investment in the fund, or the fund may not perform as well as other investments, if:

Compared to mutual funds that focus only on large capitalization companies, the fund’s share price may be more volatile because the fund may invest a significant portion of its assets in small and medium capitalization companies.

Compared to large companies, small and medium capitalization companies are more likely to have:

Further, securities of small and medium capitalization companies are more likely to:

Who may want to invest

The fund may be an appropriate investment if you:

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Performance information

The following shows summary performance information for the fund in a bar chart and an Average Annual Total Returns table. The information provides an indication of the risks of investing in the fund by showing changes in the performance of Class A shares from year to year and by showing how the average annual total returns of Class A shares compare with the returns of broad-based securities market indices and an index of similar funds. The bar chart and the information below show performance of the fund’s Class A shares, but do not reflect the impact of sales charges (loads). If they did, the returns would be lower than those shown. Unlike the bar chart, the performance for Class A shares in the Average Annual Total Returns table reflects the impact of the maximum sales charge (load) applicable to the class, and, where indicated, the performance for Class A shares reflects the impact of taxes paid on distributions and the redemption of shares at the end of the period. The performance information shown below includes that of the fund’s predecessor. No performance information is presented for Class IS shares because no Class IS shares were offered prior to the date of this Prospectus. The returns of Class IS shares would differ from those of Class A to the extent that the classes bear different expenses. Class IS and Class A are invested in the same portfolio of securities. Class A shares are not offered in this Prospectus. The fund’s past performance, before and after taxes, is not necessarily an indication of how the fund will perform in the future.

Highest and lowest quarter returns (for periods shown in the bar chart)

Highest: 21.97% in 2nd quarter 2003; Lowest: (21.84)% in 3rd quarter 2002

Year to date:         % through June 30, 2008

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Fee table

This table sets forth the fees and expenses you may pay if you invest in Class IS shares.

Example

This example helps you compare the costs of investing in the fund with the costs of investing in other mutual funds. Your actual costs may be higher or lower. The example assumes:

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More on the fund’s investments

The fund’s investment objective and principal investment strategies are described under the section entitled “Investments, risks and performance” above. This section provides further information about the investment strategies that may be used by the fund.

The fund’s investment objective may be changed by the Board of Trustees without shareholder approval.

Derivatives and hedging techniques

The fund may, but need not, use derivative contracts, such as futures and options on securities, securities indices or currencies; options on these futures; forward currency contracts; and interest rate or currency swaps for any of the following purposes:

A derivative contract will obligate or entitle the fund to deliver or receive an asset or cash payment based on the change in value of one or more securities, currencies or indices. Even a small investment in derivative contracts can have a big impact on the fund’s stock market, currency and interest rate exposure. Therefore, using derivatives can disproportionately increase losses and reduce opportunities for gains when stock prices, currency rates or interest rates are changing. The fund may not fully benefit from or may lose money on derivatives if changes in their value do not correspond accurately to changes in the value of the fund’s holdings.

The other parties to certain derivative contracts present the same types of credit risk as issuers of fixed income securities. Derivatives also can make the fund less liquid and harder to value, especially in declining markets.

Securities of other investment companies

The fund may invest up to 10% of its assets in securities of other investment companies, including shares in a portfolio of securities that seeks to track the performance of an underlying equity index or a portion of an equity index.

Defensive investing

The fund may depart from its principal investment strategies in response to adverse market, economic or political conditions by taking temporary defensive positions in any type of money market instruments and short-term debt

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securities or cash without regard to any percentage limitations. If the fund takes a temporary defensive position, it may be unable to achieve its investment objective.

Other information

The fund may also use other strategies and invest in other securities that are described, along with their risks, in the Statement of Additional Information (“SAI”). However, the fund may not use all of the strategies and techniques or invest in all of the types of securities described in this Prospectus or in the SAI. Also note that there are many other factors, which are not described here, that could adversely affect your investment and that could prevent the fund from achieving its investment objective.

Portfolio holdings

The fund’s policies and procedures with respect to the disclosure of the fund’s portfolio securities are described in the SAI.

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Management

Manager and subadviser

Legg Mason Partners Fund Advisor, LLC (“LMPFA” or the “manager”) is the fund’s investment manager. LMPFA, with offices at 620 Eighth Avenue, New York, New York 10018, also serves as the investment manager of other Legg-Mason sponsored funds. LMPFA provides administrative and certain oversight services to the fund and manages the fund’s cash and short-term instruments. As of December 31, 2007, LMPFA’s total assets under management were approximately $193 billion.

ClearBridge Advisors, LLC (“ClearBridge” or the “subadviser”) provides the day-to-day portfolio management of the fund. ClearBridge has offices at 620 Eighth Avenue, New York, New York 10018 and is an investment adviser that was formed to succeed to the equity securities portfolio management business of Citigroup Asset Management (“CAM”), which was acquired by Legg Mason, Inc. (“Legg Mason”) in December 2005. As of December 31, 2007, ClearBridge’s total assets under management were approximately $100.5 billion.

LMPFA and ClearBridge are wholly-owned subsidiaries of Legg Mason. Legg Mason, whose principal executive offices are at 100 Light Street, Baltimore, Maryland 21202, is a global asset management company. As of December 31, 2007, Legg Mason’s asset management operation had aggregate assets under management of approximately $998 billion.

Portfolio managers

John G. Goode and Peter J. Hable serve as co-portfolio managers and are responsible for the day-to-day management of the fund. Each is an investment officer of ClearBridge. Mr. Goode has been with ClearBridge or its predecessor companies since 1969. Mr. Hable has been with ClearBridge or its predecessor companies since 1983. Mr. Goode has over 37 years of investment management experience and Mr. Hable has 23 years of investment management experience. Both Mr. Goode and Mr. Hable have been involved in the day-to-day management of the fund’s portfolio since November 1990.

The SAI provides information about the compensation of the portfolio managers, other accounts they manage, and any fund shares held by the portfolio managers.

Management fee

For the fiscal year ended September 30, 2007, the fund paid fees of 0.64% of the fund’s average daily net assets for management services.

A discussion regarding the basis for the Board’s approval of the fund’s current management agreement and subadvisory agreement is available in the fund’s Semi-Annual Report for the fiscal period ended March 31, 2008.

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Distribution plans

Legg Mason Investor Services, LLC (“LMIS” or the “distributor”), a wholly-owned broker/dealer subsidiary of Legg Mason, serves as the fund’s sole and exclusive distributor.

Class IS shares are not subject to any distribution and/or service fees.

The distributor may make payments for distribution and/or shareholder servicing activities out of its past profits and other available sources. The distributor may also make payments to dealers for marketing, promotional or related expenses. The amount of these payments is determined by the distributor and may be substantial. The manager or an affiliate may make similar payments under similar arrangements.

The payments described in the paragraph above are often referred to as “revenue sharing payments.” The recipients of such payments may include the fund’s distributor, affiliates of the manager, broker/dealers, financial institutions and other financial intermediaries through which investors may purchase shares of the fund. In some circumstances, such payments may create an incentive for an intermediary or its employees or associated persons to recommend or sell shares of the fund to you. Please contact your financial intermediary for details about revenue sharing payments it may receive.

Recent developments

On May 31, 2005, the SEC issued an order in connection with the settlement of an administrative proceeding against Smith Barney Fund Management LLC (“SBFM”), the then-investment adviser or manager to the fund, and Citigroup Global Markets Inc. (“CGMI”), a former distributor of the fund, relating to the appointment of an affiliated transfer agent for the Smith Barney family of mutual funds, including the fund (the “Affected Funds”). The SEC order found that SBFM and CGMI willfully violated Section 206(1) of the Investment Advisers Act of 1940, as amended, and the rules promulgated thereunder (the “Advisers Act”). Specifically, the order found that SBFM and CGMI knowingly or recklessly failed to disclose to the boards of the Affected Funds in 1999 when proposing a new transfer agent arrangement with an affiliated transfer agent that: First Data Investors Services Group (“First Data”), the Affected Funds’ then-existing transfer agent, had offered to continue as transfer agent and do the same work for substantially less money than before; and that CAM, the Citigroup Inc. (“Citigroup”) business unit that, at the time, included the Affected Funds’ investment manager and other investment advisory companies, had entered into a side letter with First Data under which CAM agreed to recommend the appointment of First Data as sub-transfer agent to the affiliated transfer agent in exchange for, among other things, a guarantee by First Data of specified amounts of asset management and investment banking fees to CAM and CGMI. The order also found that SBFM and CGMI willfully

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violated Section 206(2) of the Advisers Act by virtue of the omissions discussed above and other misrepresentations and omissions in the materials provided to the Affected Funds’ boards, including the failure to make clear that the affiliated transfer agent would earn a high profit for performing limited functions while First Data continued to perform almost all of the transfer agent functions, and the suggestion that the proposed arrangement was in the Affected Funds’ best interests and that no viable alternatives existed.

SBFM and CGMI do not admit or deny any wrongdoing or liability. The settlement does not establish wrongdoing or liability for purposes of any other proceeding. The SEC censured SBFM and CGMI and ordered them to cease and desist from violations of Sections 206(1) and 206(2) of the Advisers Act. The order required Citigroup to pay $208.1 million, including $109 million in disgorgement of profits, $19.1 million in interest, and a civil money penalty of $80 million. Approximately $24.4 million has already been paid to the Affected Funds, primarily through fee waivers. The remaining $183.7 million, including the penalty, has been paid to the U.S. Treasury and will be distributed pursuant to a plan submitted for the approval of the SEC. At this time, there is no certainty as to how the above-described proceeds of the settlement will be distributed, to whom such distributions will be made, the methodology by which such distributions will be allocated, and when such distributions will be made. The order also required that transfer agency fees received from the Affected Funds since December 1, 2004, less certain expenses, be placed in escrow and provided that a portion of such fees might be subsequently distributed in accordance with the terms of the order. On April 3, 2006, an aggregate amount of approximately $9 million held in escrow was distributed to the Affected Funds.

The order required SBFM to recommend a new transfer agent contract to the Affected Funds’ boards within 180 days of the entry of the order; if a Citigroup affiliate submitted a proposal to serve as transfer agent or sub-transfer agent, SBFM and CGMI would have been required, at their expense, to engage an independent monitor to oversee a competitive bidding process. On November 21, 2005, and within the specified timeframe, the Affected Funds’ boards selected a new transfer agent for the Affected Funds. No Citigroup affiliate submitted a proposal to serve as transfer agent. Under the order, SBFM also must comply with an amended version of a vendor policy that Citigroup instituted in August 2004.

Although there can be no assurance, the manager does not believe that this matter will have a material adverse effect on the Affected Funds.

On December 1, 2005, Citigroup completed the sale of substantially all of its global asset management business, including SBFM, to Legg Mason.

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Retirement and institutional investors — Eligible Investors

Class IS shares may be purchased only by Retirement Plans with omnibus accounts held on the books of the fund and Institutional Investors. In order to purchase Class IS shares, an investor must hold its shares in one account with the fund.

“Retirement Plans” include 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit-sharing plans, non-qualified deferred compensation plans and other similar employer-sponsored retirement plans. Retirement Plans do not include individual retirement vehicles, such as traditional and Roth IRAs, Coverdell education savings accounts, individual 403(b)(7) custodial accounts, Keogh plans, SEPs, SARSEPs, SIMPLE IRAs, or Section 529 savings accounts. Although Retirement Plans with omnibus accounts held on the books of the fund are not subject to minimum initial or subsequent investment requirements for Class IS shares, certain investment minimums may be imposed by a financial intermediary.

“Institutional Investors” generally include corporations, banks, trust companies, insurance companies, investment companies, foundations, endowments, defined benefit plans and other similar entities.

Institutional Investors may invest in Class IS shares if they meet the $1,000,000 minimum initial investment requirement. There is no minimum subsequent investment requirement for Institutional Investors. In order to purchase Class IS shares, an investor must hold its shares in one account with the fund.

Plan sponsors, plan fiduciaries and other financial intermediaries may choose to impose qualification requirements for plans that differ from the fund’s share class eligibility standards. In certain cases this could result in the selection of a share class with higher service and distribution-related fees than otherwise would have been charged. The fund is not responsible for, and has no control over, the decision of any plan sponsor, plan fiduciary or financial intermediary to impose such differing requirements. Please consult with your plan sponsor, plan fiduciary or financial intermediary for more information about available share classes.

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Buying shares

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Other things to know about transactions

When you buy, exchange or redeem shares, your request must be in good order. This means you have provided the following information, without which your request may not be processed:

The fund’s transfer agent or Legg Mason Partners Shareholder Services will employ reasonable procedures to confirm that any telephone exchange or redemption request is genuine, which may include recording calls, asking the caller to provide certain personal identification information, sending you a written confirmation or requiring other confirmation procedures from time to time. If these procedures are followed, neither the fund nor its agents will bear any liability for such transactions.

Signature guarantees

To be in good order, your redemption request must include a signature guarantee if you:

You can obtain a signature guarantee from most banks, dealers, brokers, credit unions and federal savings and loan institutions, but not from a notary public.

The fund has the right to:

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Small account balances/Mandatory redemptions

If at any time the aggregate value of the fund shares in your account is less than $500 for any reason (including solely due to declines in net asset value and/or failure to invest at least $500 within a reasonable period), the fund reserves the right to ask you to bring your account up to the applicable minimum investment amount as determined by your Service Agent. In such case you shall be notified in writing and will have 60 days to make an additional investment to bring your account value up to the required level. If you choose not to do so within this 60-day period, the fund may close your account and send you the redemption proceeds. In the event your account is closed due to a failure to increase your balance to the minimum required amount, you will not be eligible to have your account subsequently reinstated without imposition of any sales charges that may apply to your new purchase. The fund may, with prior notice, change the minimum size of accounts subject to mandatory redemption, which may vary by class, or implement fees for small accounts.

Subject to applicable law, the fund may, with prior notice, adopt other policies from time to time requiring mandatory redemption of shares in certain circumstances.

For more information, please contact your Service Agent or Legg Mason Partners Shareholder Services or consult the SAI.

Frequent purchases and redemptions of fund shares

Frequent purchases and redemptions of fund shares may interfere with the efficient management of the fund’s portfolio by its portfolio managers, increase portfolio transaction costs, and have a negative effect on the fund’s long-term shareholders. For example, in order to handle large flows of cash into and out of the fund, the portfolio managers may need to allocate more assets to cash or other short-term investments or sell securities, rather than maintaining full investment in securities selected to achieve the fund’s investment objective. Frequent trading may cause the fund to sell securities at less favorable prices. Transaction costs, such as brokerage commissions and market spreads, can detract from the fund’s performance. In addition, the return received by long-term shareholders may be reduced when trades by other shareholders are made in an effort to take advantage of certain pricing discrepancies, when, for example, it is believed that the fund’s share price, which is determined at the close of the NYSE on each trading day, does not accurately reflect the value of the fund’s portfolio securities. Funds investing in foreign securities have been

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particularly susceptible to this form of arbitrage, but other funds could also be affected.

Because of the potential harm to funds in the Legg Mason Partners funds complex and their long-term shareholders, the Board of the fund has approved policies and procedures that are intended to discourage and prevent excessive trading and market timing abuses through the use of various surveillance techniques. Under these policies and procedures, the fund may limit additional exchanges or purchases of fund shares by shareholders who are believed by the manager to be engaged in these abusive trading activities in the fund or in other funds within the fund complex. In the event that an exchange request is rejected, the shareholder may nonetheless redeem its shares. The intent of the policies and procedures is not to inhibit legitimate strategies, such as asset allocation, dollar cost averaging, or similar activities that may nonetheless result in frequent trading of fund shares.

Under the fund’s policies and procedures, the fund reserves the right to restrict or reject purchases of shares (including exchanges) without prior notice whenever a pattern of excessive trading by a shareholder is detected within the fund complex. A committee established by the manager administers the policy. The policy provides that the committee will use its best efforts to restrict a shareholder’s trading privileges in the Legg Mason Partners funds complex if that shareholder has engaged in a total of four or more “Round Trips” (as defined below) across all Legg Mason Partners funds during any rolling 12-month period. However, the committee has the discretion to determine that restricting a shareholder’s trading privileges is not necessary (or that a new limit on Round Trips should be established for the shareholder) if it is determined that the pattern of trading is not abusive or harmful. In making such a determination, the committee will consider, among other things, the nature of the shareholder’s account, the reason for the frequent trading, the amount of trading and the particular funds in which the trading has occurred. Additionally, the committee has the discretion to make inquiries or to take action against any shareholder whose trading appears inconsistent with the frequent trading policy. Examples of the types of actions the committee may take to deter excessive trading in a shareholder account include restricting the shareholder from purchasing additional shares in the fund altogether or imposing other restrictions (such as requiring purchase orders to be submitted by mail) that would deter the shareholder from trading frequently in the funds.

A “Round Trip” is defined as a purchase (including subscriptions and exchanges) into the fund followed by a sale (including redemptions and exchanges) of the same or a similar number of shares out of the fund within 30 days of such purchase. Purchases and sales of the fund’s shares pursuant to an automatic investment plan or similar program for periodic transactions are not considered in determining Round Trips. For purposes of these policies and procedures, the

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Legg Mason Partners funds complex also includes certain Western Asset funds and Barrett Opportunity Fund, Inc., but does not include money market funds in the fund complex.

The policies apply to any account, whether an individual account, accounts with financial intermediaries such as investment advisers, broker/dealers or retirement plan administrators, commonly called omnibus accounts, where the intermediary holds fund shares for a number of its customers in one account. The fund’s ability to monitor trading in omnibus accounts may, however, be severely limited due to the lack of access to an individual investor’s trading activity when orders are placed through these types of accounts. There may also be operational and technological limitations on the ability of the fund’s service providers to identify or terminate frequent trading activity within the various types of omnibus accounts. The fund’s distributor has entered into agreements with intermediaries requiring the intermediaries to, among other things, help identify frequent trading activity and to prohibit further purchases or exchanges by a shareholder identified as having engaged in frequent trading. These agreements took effect on October 16, 2007.

The fund’s policies also require personnel such as the portfolio managers and investment staff to report any abnormal or otherwise suspicious investment activity, and prohibit short-term trades by such personnel for their own account in mutual funds managed by the manager and its affiliates, other than money market funds. Additionally, the fund has adopted policies and procedures to prevent the selective release of information about the fund’s portfolio holdings, as such information may be used for market-timing and similar abusive practices.

The fund’s policies provide for ongoing assessment of the effectiveness of current policies and surveillance tools, and the Board reserves the right to modify these or adopt additional policies and restrictions in the future. Shareholders should be aware, however, that any surveillance techniques currently employed by the fund or other techniques that may be adopted in the future may not be effective, particularly where the trading takes place through certain types of omnibus accounts. As noted above, if the fund is unable to detect and deter trading abuses, the fund’s performance, and its long-term shareholders, may be harmed. In addition, shareholders may be harmed by the extra costs and portfolio management inefficiencies that result from frequent trading of fund shares, even when the trading is not for abusive purposes. Furthermore, the fund may not apply its policies consistently or uniformly, resulting in the risk that some shareholders may be able to engage in frequent trading while others will bear the costs and effects of that trading. The fund will provide advance notice to shareholders and prospective investors of any specific restrictions on the trading of fund shares that the Board may adopt in the future.

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Share certificates

The fund does not issue share certificates.

Record ownership

If you hold shares through a Service Agent, your Service Agent may establish and maintain your account and be the shareholder of record. In the event that the fund holds a shareholder meeting, your Service Agent, as record holder, will vote your shares in accordance with your instructions. If you do not give your Service Agent voting instructions, your Service Agent may nonetheless, under certain circumstances, be entitled to vote your shares.

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Dividends, distributions and taxes

Dividends and distributions

The fund generally pays dividends and makes capital gain distributions, if any, typically once or twice a year. The fund may pay additional distributions and dividends at other times if necessary for the fund to avoid a federal tax. The fund expects distributions to be primarily from capital gain. Unless otherwise directed, capital gain distributions and dividends are reinvested in additional fund shares of the same class you hold. You do not pay a sales charge on reinvested distributions or dividends. Alternatively, you can instruct your Service Agent or Legg Mason Partners Shareholder Services to have your distributions and/or dividends paid in cash. You can change your choice at any time to be effective as of the next distribution or dividend.

Taxes

In general, redeeming shares, exchanging shares and receiving dividends and distributions (whether in cash or additional shares) are all taxable events.

The following table summarizes the tax status to you of certain transactions related to the funds.

Distributions attributable to short-term capital gains are treated as dividends, taxable as ordinary income. Dividends and long-term capital gain distributions are taxable whether received in cash or reinvested in additional fund shares. Although dividends (including dividends from short-term capital gains) are generally taxable as ordinary income for taxable years beginning before January 1, 2011, individual shareholders who satisfy certain holding period and other requirements are taxed on such dividends at long-term capital gain rates to the extent the dividends are attributable to “qualified dividend income” received by the fund. “Qualified dividend income” generally consists of dividends received from U.S. corporations (other than dividends from tax-exempt organizations and certain dividends from real estate investment trusts and regulated investment companies) and certain foreign corporations.

Long-term capital gain distributions are taxable to you as long-term capital gain regardless of how long you have owned your shares. You may want to avoid buying shares when the fund is about to declare a capital gain distribution or a dividend, because it will be taxable to you even though it may actually be a return of a portion of your investment.

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After the end of each year, your Service Agent or the fund will provide you with information about the distributions and dividends you received and any redemptions of shares during the previous year. If you do not provide the fund with your correct taxpayer identification number and any required certifications, you may be subject to back-up withholding on your distributions, dividends, and redemption proceeds. Because each shareholder’s circumstances are different and special tax rules may apply, you should consult your tax adviser about your investment in the fund.

The above discussion is applicable to shareholders who are U.S. persons. If you are a non-U.S. person, please consult your own tax adviser with respect to the tax consequences to you of an investment in the fund.

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Share price

You may buy, exchange or redeem shares at their net asset value next determined after receipt of your request in good order, plus any applicable sales charge. For each class of shares, net asset value per share is the value of its assets minus its liabilities divided by the number of shares outstanding. Net asset value is calculated separately for each class of shares. The fund calculates its net asset value every day the NYSE is open. This calculation is done when regular trading closes on the NYSE (normally 4:00 p.m., Eastern time). The NYSE is closed on certain holidays listed in the SAI.

The Board has approved procedures to be used to value the fund’s securities for the purposes of determining the fund’s net asset value. The valuation of the securities of the fund is determined in good faith by or under the direction of the Board. The Board has delegated certain valuation functions for the fund to the manager.

The fund generally values its securities based on market prices determined at the close of regular trading on the NYSE. The fund’s currency valuations, if any, are done as of when the London Stock Exchange closes, which is usually at 12 noon Eastern time, as the manager believes that these valuations typically reflect the largest trading volume in the foreign currency markets. A material change in the value of currency during the period between the close of the London Stock Exchange and the calculation of the fund’s net asset value on the same date is considered a significant event, as described below, in response to which the fund may use fair valuation procedures to value the affected investments. For equity securities that are traded on an exchange, the market price is usually the closing sale or official closing price on that exchange. In the case of securities not traded on an exchange, or if such closing prices are not otherwise available, the market price is typically determined by independent third party pricing vendors approved by the fund’s Board using a variety of pricing techniques and methodologies. Short-term debt obligations that will mature in 60 days or less are valued at amortized cost, unless it is determined that using this method would not reflect an investment’s fair value. If vendors are unable to supply a price, or if the price supplied is deemed by the manager to be unreliable, the market price may be determined using quotations received from one or more broker/dealers that make a market in the security. When such prices or quotations are not available, or when the manager believes that they are unreliable, the manager may price securities using fair value procedures approved by the Board. Because the fund invests in securities of small capitalization companies — some of which may be thinly traded, for which market quotations may not be readily available or may be unreliable — the fund may use fair valuation procedures more frequently than funds that invest primarily in securities that are more liquid, such as securities of large capitalization domestic issuers. The fund may also use fair value procedures if the manager determines that a significant event has occurred between the time at which a market price is determined and the time at which

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the fund’s net asset value is calculated. In particular, the value of foreign securities may be materially affected by events occurring after the close of the market on which they are valued, but before the fund prices its shares. The fund uses a fair value model developed by an independent third party pricing service to price foreign equity securities on days when there is a certain percentage change in the value of a domestic equity security index, as such percentage may be determined by the manager from time to time.

Valuing securities at fair value involves greater reliance on judgment than valuation of securities based on readily available market quotations. A fund that uses fair value to price securities may value those securities higher or lower than another fund using market quotations or its own fair value methodologies to price the same securities. There can be no assurance that the fund could obtain the fair value assigned to a security if it were to sell the security at approximately the time at which the fund determines its net asset value.

The fund may invest in securities that are listed on foreign exchanges that trade on weekends and other days when the fund does not price its shares. Therefore, the value of the fund’s shares may change on days when you will not be able to purchase or redeem the fund’s shares.

In order to buy, redeem or exchange shares at that day’s price, you must place your order with your Service Agent or Legg Mason Partners Shareholder Services before the NYSE closes. If the NYSE closes early, you must place your order prior to the actual closing time.

It is the responsibility of the Service Agents to transmit all orders to buy, exchange or redeem shares to the transfer agent on a timely basis.

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Financial highlights

The financial highlights tables are intended to help you understand the performance of Class A shares of the fund for the past 5 years. Class IS and Class A are invested in the same portfolio of securities. No financial highlights are provided for Class IS shares as the fund commenced the offering of such shares as of the date of this Prospectus. The returns for Class IS shares will differ from those of Class A to the extent that their expenses differ. Certain information reflects financial results for a single share. Total return represents the rate that a shareholder would have earned (or lost) on a fund share assuming reinvestment of all dividends and distributions. The information in the following tables has been derived from the fund’s and the predecessor fund’s financial statements. Except for the financial highlights for the six months ended March 31, 2008, which are unaudited, these financial statements have been audited by                 , an independent registered public accounting firm, whose report, along with the fund’s financial statements, is included in the annual report (available upon request). The financial information shown below for periods prior to April 16, 2007 is that of the fund’s predecessor.

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Legg Mason Partners Funds Privacy Policy

[This page is not part of the prospectus.]

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Legg Mason Partners Fundamental Value Fund

(Investment Company Act

file no. 811-06444)

FD0206 7/08

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PROSPECTUS / JULY     , 2008

Legg Mason Partners

International All Cap Opportunity Fund Class IS Shares

The Securities and Exchange Commission has not approved or disapproved these securities or determined whether this prospectus is accurate or complete. Any statement to the contrary is a crime.

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This Prospectus offers Class IS shares of the fund. Class IS shares are sold with no front-end sales charge or contingent deferred sales charge only to Retirement Plans with omnibus accounts held on the books of the fund and Institutional Investors. See “Retirement and institutional investors” for additional information.

As part of a number of initiatives launched in 2006 to restructure and streamline the Legg Mason Partners fund complex, the fund assumed the assets and liabilities of a predecessor fund with the same name, effective April 16, 2007. Any information in this Prospectus relating to the fund prior to April 16, 2007 relates to the fund’s predecessor.

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Investments, risks and performance

Investment objective

The fund seeks total return on its assets from growth of capital and income.

Principal investment strategies

Key investments

The fund invests primarily in equity securities of foreign companies. Equity securities include exchange traded and over-the-counter common stocks and preferred shares, debt securities convertible into equity securities, and warrants and rights relating to equity securities. Under normal circumstances, the fund invests at least 80% of the value of its net assets in a diversified portfolio of equity securities and may invest up to 20% of the value of its net assets in bonds, notes and debt securities (including up to 10% of the value of its net assets in below investment grade securities (commonly known as “junk bonds”)).

Selection process

The portfolio managers emphasize individual security selection while diversifying the fund’s investments across regions and countries which may help to reduce risk. While the portfolio managers select investments primarily for their capital appreciation potential, some investments have an income component as well. Companies in which the fund invests may have large, mid or small size market capitalizations and may operate in any market sector. Market conditions around the world change constantly as does the location of potential investment opportunities. Depending on the portfolio managers’ assessment of overseas potential for long-term growth, the fund’s emphasis among foreign markets (including emerging markets) and types of issuers may vary.

In selecting individual companies for investment, the portfolio managers look for the following:

By spreading the fund’s investments across many international markets, the portfolio managers seek to reduce volatility compared to an investment in a

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single region. Unlike global mutual funds which may allocate a substantial portion of assets to the U.S. markets, the fund invests substantially all of its assets in countries outside of the United States.

In allocating assets among countries and regions, the economic and political factors the portfolio managers evaluate include:

Principal risks of investing in the fund

Investing in foreign securities can bring benefits, but it may also involve risks. Investors could lose money on their investment in the fund, or the fund may not perform as well as other investments, as a result of the following risks:

The fund invests in certain foreign countries where the securities markets are less liquid and more volatile than markets in the United States. In some foreign countries, less information is available about issuers and markets because of less rigorous accounting and regulatory standards than in the United States. Currency fluctuations could erase investment gains or add to investment losses. The risks of investing in emerging markets are substantially greater than the risks of investing in more developed markets.

The fund may invest up to 20% of its assets in debt securities of foreign corporate and governmental issuers as well as U.S. government securities and money market obligations of U.S. issuers. The fund may invest in all types of debt securities of any maturity or credit quality. These securities may be denominated in U.S. dollars or other currencies and may pay fixed or variable rates of interest. The value of debt securities will go down if interest rates go up, the credit rating of the security is downgraded or the issuer defaults on its obligation to pay principal or interest. These risks are greater for debt securities rated below investment grade.

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The fund may invest up to 10% of its assets in below investment grade securities, commonly known as “junk bonds.” Below investment grade securities are speculative and their issuers may have diminished capacity to pay principal and interest. These securities have a higher risk of default, tend to be less liquid and may be more difficult to value.

Who may want to invest

The fund may be an appropriate investment if you:

Performance information

The following shows summary performance information for the fund in a bar chart and an Average Annual Total Returns table. The information provides an indication of the risks of investing in the fund by showing changes in the performance of Class A shares from year to year and by showing how the average annual returns of Class A shares compare with the returns of a broad-based securities market index. The bar chart shows performance of the fund’s Class A shares, but does not reflect the impact of sales charges (loads). If it did, the returns would be lower than those shown. Unlike the bar chart, the performance for Class A  shares in the Average Annual Total Returns table reflects the impact of the maximum sales charge (load) applicable to the class and, where indicated, the performance for Class A shares reflects the impact of taxes paid on distributions and the redemption of shares at the end of the period. The performance information shown below includes that of the fund’s predecessor. No performance information is presented for Class IS shares because no Class IS shares were offered prior to the date of this Prospectus. Class IS and Class A are invested in the same portfolio of securities. Class A shares are not offered in this Prospectus. The returns of Class IS shares would differ from those of Class A to the extent that the classes bear different expenses. The fund’s past performance is not necessarily an indication of how the fund will perform in the future.

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Highest and lowest quarterly returns for periods shown in the bar chart:

Highest: 42.91% in 4th quarter 1999; Lowest: (21.01)% in 3rd quarter 2001

Year to date:         % through June 30, 2008

Fee table

This table sets forth the fees and expenses you may pay if you invest in Class IS shares.

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Example

This example helps you compare the costs of investing in the fund with the costs of investing in other mutual funds. Your actual costs may be higher or lower. The example assumes:

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More on the fund’s investments

The fund’s investment objective and principal investment strategies are described under the section entitled “Investments, risks and performance” above. This section provides further information about the investment strategies that may be used by the fund.

The fund’s investment objective may be changed by the Board of Trustees without shareholder approval.

Currency transactions

The fund may enter into transactions to buy or sell currencies at a future date, which may be a few days or a number of months. The fund may enter into these forward currency contracts to:

The fund may not fully benefit from or may lose money on forward currency transactions if changes in currency rates do not occur as anticipated or do not correspond accurately to changes in the value of the fund’s holdings.

Emerging markets

The fund may invest in issuers located or doing business in emerging markets. Emerging market investments offer the potential of significant gains but also involve greater risks than investing in more developed countries. Political or economic stability, lack of market liquidity and government actions such as currency controls or seizure of private businesses or property are more likely in emerging markets.

Defensive investing

The fund may depart from its principal investment strategies in response to adverse market, economic or political conditions by taking temporary defensive positions in any type of money market instruments and short-term debt securities or cash without regard to any percentage limitations. If the fund takes a temporary defensive position, it may be unable to achieve its investment objective.

Portfolio holdings

The fund’s policies and procedures with respect to the disclosure of the fund’s portfolio securities are described in the Statement of Additional Information (“SAI”).

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Other information

The fund also may use other strategies and invest in other securities that are described, along with their risks, in the SAI. However, the fund might not use all of the strategies and techniques or invest in all of the types of securities described in this Prospectus or in the SAI. Also note that there are many other factors, which are not described here, that could adversely affect your investment and that could prevent the fund from achieving its investment objective.

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Management

Manager and subadviser

Legg Mason Partners Fund Advisor, LLC (“LMPFA” or the “manager”) is the fund’s investment manager. LMPFA, with offices at 620 Eighth Avenue, New York, New York 10018, also serves as the investment manager of other Legg Mason-sponsored funds. LMPFA provides administrative and certain oversight services to the fund and manages the fund’s cash and short-term instruments. As of December 31, 2007, LMPFA’s total assets under management were approximately $193 billion.

Global Currents Investment Management, LLC (“GCIM” or the “subadviser”) provides day-to-day portfolio management services to the fund. GCIM, with offices at Delaware Corporate Center II, Suite 100, 2 Righter Parkway, Wilmington, Delaware 19803, is a newly organized subsidiary of Legg Mason, Inc. (“Legg Mason”). GCIM was created as part of an internal reorganization of Legg Mason’s international investment resources that resulted in the investment team that manages the fund being transferred from Brandywine Global Investment Management, LLC (“Brandywine”) to GCIM. The reorganization did not result in any changes to the investment team that manages the fund. GCIM replaced Brandywine as the fund’s subadviser on July 1, 2008. As of July 1, 2008, GCIM’s total assets under management were approximately $        billion

LMPFA is also a wholly owned subsidiary of Legg Mason. Legg Mason, whose principal executive offices are at 100 Light Street, Baltimore, Maryland 21202, is a global asset management company. As of December 31, 2007, Legg Mason’s asset management operation had aggregate assets under management of approximately $998 billion.

Portfolio managers

Paul D. Ehrlichman, Sean M. Bogda and Safa R. Muhtaseb have provided portfolio management services to the fund since December 2006.

Paul Ehrlichman is the chairman and chief investment officer of GCIM. Prior to July, 2008, he served as Global Equity CIO at Brandywine, where he managed the international and global value equity team, originally joining Brandywine in 1988. Mr. Erhlichman has 25 years of investment experience. He earned a B.S. degree in Finance and Quantitative Analysis from La Salle University, graduating Cum Laude.

Sean Bogda is a managing director of GCIM and a portfolio manager on the International and Global Value Equity team at GCIM. He is responsible for covering the energy, industrials, and consumer discretionary sectors. Sean was previously with Brandywine as global equity portfolio manager (1993-2008). He is a CFA Charterholder and earned a B.S. in Finance from the University of Colorado, graduating Cum Laude.

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Safa Muhtaseb is a managing director at GCIM and is a portfolio manager on the International and Global Value Equity team at GCIM. He contributes knowledge and experience in research of investments across countries and sectors, while contributing insights and stock recommendations for the firm’s equity strategies. Safa was previously with Brandywine as global equity portfolio manager (2004-2008), bringing with him over 20 years of industry experience. He was also with Goldman Sachs Asset Management as senior portfolio manager for global and international products (2001-2004). Safa is a CFA Charterholder, earned an M.B.A. in Finance from the University of Tennessee, and graduated cum laude with a B.S. in Business Administration from Old Dominion University.

The SAI provides information about the compensation of the portfolio managers, other accounts they manage, and any fund shares held by the portfolio managers.

Management fee

For the fiscal year ended October 31, 2007, the fund paid a management fee of 0.85% of the fund’s average daily net assets for management services.

A discussion regarding the basis for the Board’s approval of the fund’s management agreement and subadvisory agreements with Brandywine and GCIM is available in the fund’s Semi-Annual Report for the period ended April 30, 2008.

Distribution plan

Legg Mason Investor Services, LLC (“LMIS” or the “distributor”), a wholly-owned broker-dealer subsidiary of Legg Mason, serves as the fund’s sole and exclusive distributor.

Class IS shares are not subject to any distribution and/or service fees.

The distributor may make payments for distribution and/or shareholder servicing activities out of its past profits and other available sources. The distributor may also make payments to dealers for marketing, promotional or related expenses. The amount of these payments is determined by the distributor and may be substantial. The manager or an affiliate may make similar payments under similar arrangements.

The payments described in the paragraph above are often referred to as “revenue sharing payments.” The recipients of such payments may include the fund’s distributor, affiliates of the manager, broker/dealers, financial institutions and other financial intermediaries through which investors may purchase shares of the fund. In some circumstances, such payments may create an incentive for an intermediary or its employees or associated persons

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to recommend or sell shares of the fund to you. Please contact your financial intermediary for details about revenue sharing payments it may receive.

Recent developments

On May 31, 2005, the SEC issued an order in connection with the settlement of an administrative proceeding against Smith Barney Fund Management LLC (“SBFM”), the then-investment adviser or manager to the fund, and Citigroup Global Markets Inc. (“CGMI”), a former distributor of the fund, relating to the appointment of an affiliated transfer agent for the Smith Barney family of mutual funds, including the fund (the “Affected Funds”). The SEC order found that SBFM and CGMI willfully violated Section 206(1) of the Investment Advisers Act of 1940, as amended, and the rules promulgated thereunder (the “Advisers Act”). Specifically, the order found that SBFM and CGMI knowingly or recklessly failed to disclose to the boards of the Affected Funds in 1999 when proposing a new transfer agent arrangement with an affiliated transfer agent that: First Data Investors Services Group (“First Data”), the Affected Funds’ then-existing transfer agent, had offered to continue as transfer agent and do the same work for substantially less money than before; and that Citigroup Asset Management (“CAM”), the Citigroup Inc. (“Citigroup”) business unit that, at the time, included the Affected Funds’ investment manager and other investment advisory companies, had entered into a side letter with First Data under which CAM agreed to recommend the appointment of First Data as sub-transfer agent to the affiliated transfer agent in exchange for, among other things, a guarantee by First Data of specified amounts of asset management and investment banking fees to CAM and CGMI. The order also finds that SBFM and CGMI willfully violated Section 206(2) of the Advisers Act by virtue of the omissions discussed above and other misrepresentations and omissions in the materials provided to the Affected Funds’ boards, including the failure to make clear that the affiliated transfer agent would earn a high profit for performing limited functions while First Data continued to perform almost all of the transfer agent functions, and the suggestion that the proposed arrangement was in the Affected Funds’ best interests and that no viable alternatives existed.

SBFM and CGMI do not admit or deny any wrongdoing or liability. The settlement does not establish wrongdoing or liability for purposes of any other proceeding. The SEC censured SBFM and CGMI and ordered them to cease and desist from violations of Sections 206(1) and 206(2) of the Advisers Act. The order required Citigroup to pay $208.1 million, including $109 million in disgorgement of profits, $19.1 million in interest, and a civil money penalty of $80 million. Approximately $24.4 million has already been paid to the Affected Funds, primarily through fee waivers. The remaining $183.7 million, including the penalty, has been paid to the U.S. Treasury and will be distributed pursuant to a plan submitted for the approval of the SEC. At this time, there is no

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certainty as to how the above-described proceeds of the settlement will be distributed, to whom such distributions will be made, the methodology by which such distributions will be allocated, and when such distributions will be made. The order also required that transfer agency fees received from the Affected Funds since December 1, 2004, less certain expenses, be placed in escrow and provided that a portion of such fees might be subsequently distributed in accordance with the terms of the order. On April 3, 2006, an aggregate amount of approximately $9 million held in escrow was distributed to the Affected Funds.

The order required SBFM to recommend a new transfer agent contract to the Affected Funds’ boards within 180 days of the entry of the order; if a Citigroup affiliate submitted a proposal to serve as transfer agent or sub-transfer agent, SBFM and CGMI would have been required, at their expense, to engage an independent monitor to oversee a competitive bidding process. On November 21, 2005, and within the specified timeframe, the Affected Funds’ Boards selected a new transfer agent for the Affected Funds. No Citigroup affiliate submitted a proposal to serve as transfer agent. Under the order, SBFM also must comply with an amended version of a vendor policy that Citigroup instituted in August 2004.

Although there can be no assurance, the manager does not believe that this matter will have a material adverse effect on the Affected Funds.

On December 1, 2005, Citigroup completed the sale of substantially all of its global asset management business, including SBFM, to Legg Mason.

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Retirement and institutional investors — Eligible investors

Class IS shares may be purchased only by Retirement Plans with omnibus accounts held on the books of the fund and Institutional Investors. In order to purchase Class IS shares, an investor must hold its shares in one account with the fund.

“Retirement Plans” include 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit-sharing plans, non-qualified deferred compensation plans and other similar employer-sponsored retirement plans. Retirement Plans do not include individual retirement vehicles, such as traditional and Roth individual retirement accounts, Coverdell education savings accounts, individual 403(b)(7) custodial accounts, Keogh plans, SEPs, SARSEPs, SIMPLE IRAs, or Section 529 savings accounts. Although Retirement Plans with omnibus accounts held on the books of the fund are not subject to minimum initial or subsequent investment requirements for Class IS shares, certain investment minimums may be imposed by a financial intermediary.

“Institutional Investors” generally include corporations, banks, trust companies, insurance companies, investment companies, foundations, endowments, defined benefit plans and other similar entities.

Institutional Investors may invest in Class IS shares if they meet the $1,000,000 minimum initial investment requirement. There is no minimum subsequent investment requirement for Institutional Investors. In order to purchase Class IS shares, an investor must hold its shares in one account with the fund.

Plan sponsors, plan fiduciaries and other financial intermediaries may choose to impose qualification requirements for plans that differ from the fund’s share class eligibility standards. In certain cases this could result in the selection of a share class with higher service and distribution related fees than otherwise would have been charged. The fund is not responsible for, and has no control over, the decision of any plan sponsor, plan fiduciary or financial intermediary to impose such differing requirements. Please consult with your plan sponsor, plan fiduciary or financial intermediary for more information about available share classes.

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Buying shares

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Other things to know about transactions

When you buy, exchange or redeem shares, your request must be in good order. This means you have provided the following information, without which your request may not be processed:

The fund’s transfer agent or Legg Mason Partners Shareholder Services will employ reasonable procedures to confirm that any telephone exchange or redemption request is genuine, which may include recording calls, asking the caller to provide certain personal identification information, sending you a written confirmation or requiring other confirmation procedures from time to time. If these procedures are followed, neither the fund nor its agent will bear any liability for such transactions.

Signature guarantees

To be in good order, your redemption request must include a signature guarantee if you:

You can obtain a signature guarantee from most banks, dealers, brokers, credit unions and federal savings and loan institutions, but not from a notary public.

The fund has the right to:

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Small account balances/Mandatory redemptions

If at any time the aggregate net asset value of the fund shares in your account is less than $500 for any reason (including solely due to declines in net asset value and/or failure to invest at least $500 within a reasonable period), the fund reserves the right to ask you to bring your account up to the applicable minimum investment amount as determined by your Service Agent. In such case you shall be notified in writing and will have 60 days to make an additional investment to bring your account value up to the required level. If you choose not to do so within this 60-day period, the fund may close your account and send you the redemption proceeds. In the event your account is closed due to a failure to increase your balance to the minimum required amount, you will not be eligible to have your account subsequently reinstated without imposition of any sales charges that may apply to your new purchase. The fund may, with prior notice, change the minimum size of accounts subject to mandatory redemption, which may vary by class, or implement fees for small accounts.

Subject to applicable law, the fund may, with prior notice, adopt other policies from time to time requiring mandatory redemption of shares in certain circumstances.

For more information please contact your Service Agent or Legg Mason Partners Shareholder Services or consult the SAI.

Frequent purchases and redemptions of fund shares

Frequent purchases and redemptions of fund shares may interfere with the efficient management of the fund’s portfolio by its portfolio managers, increase portfolio transaction costs, and have a negative effect on the fund’s long-term shareholders. For example, in order to handle large flows of cash into and out of the fund, the portfolio managers may need to allocate more assets to cash or other short-term investments or sell securities, rather than maintaining full investment in securities selected to achieve the fund’s investment objective. Frequent trading may cause the fund to sell securities at less favorable prices. Transaction costs, such as brokerage commissions and market spreads, can detract from the fund’s performance. In addition, the return received by long-term shareholders may be reduced when trades by other shareholders are made in an effort to take advantage of certain pricing discrepancies, when, for example, it is believed that the fund’s share price, which is determined at the

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close of the NYSE on each trading day, does not accurately reflect the value of the fund’s portfolio securities. Because the fund primarily invests in foreign securities, it may be particularly susceptible to this form of arbitrage.

Because of the potential harm to funds in the Legg Mason Partners funds complex and their long-term shareholders, the Board of the fund has approved policies and procedures that are intended to discourage and prevent excessive trading and market timing abuses through the use of various surveillance techniques. Under these policies and procedures, the fund may limit additional exchanges or purchases of fund shares by shareholders who are believed by the manager to be engaged in these abusive trading activities in the fund or in other funds within the fund complex. In the event that an exchange request is rejected, the shareholder may nonetheless redeem its shares. The intent of the policies and procedures is not to inhibit legitimate strategies, such as asset allocation, dollar cost averaging, or similar activities that may nonetheless result in frequent trading of fund shares.

Under the fund’s policies and procedures, the fund reserves the right to restrict or reject purchases of shares (including exchanges) without prior notice whenever a pattern of excessive trading by a shareholder is detected within the fund complex. A committee established by the manager administers the policy. The policy provides that the committee will use its best efforts to restrict a shareholder’s trading privileges in the Legg Mason Partners funds complex if that shareholder has engaged in a total of four or more “Round Trips” (as defined below) across all Legg Mason Partners funds during any rolling 12-month period. However, the committee has the discretion to determine that restricting a shareholder’s trading privileges is not necessary (or that a new limit on Round Trips should be established for the shareholder) if it is determined that the pattern of trading is not abusive or harmful. In making such a determination, the committee will consider, among other things, the nature of the shareholder’s account, the reason for the frequent trading, the amount of trading and the particular fund in which the trading has occurred. Additionally, the committee has the discretion to make inquiries or to take action against any shareholder whose trading appears inconsistent with the frequent trading policy. Examples of the types of actions the committee may take to deter excessive trading in a shareholder account include restricting the shareholder from purchasing additional shares in a fund altogether or imposing other restrictions (such as requiring purchase orders to be submitted by mail) that would deter the shareholder from trading frequently in the fund.

A “Round Trip” is defined as a purchase (including subscriptions and exchanges) into the fund followed by a sale (including redemptions and exchanges) of the same or a similar number of shares out of the fund within 30 days of such purchase. Purchases and sales of the fund’s shares pursuant to an automatic investment plan or similar program for periodic transactions are

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not considered in determining Round Trips. For purposes of these policies and procedures, the Legg Mason Partners funds complex also includes certain Western Asset funds and Barrett Opportunity Fund, Inc., but does not include money market funds in the fund complex.

The policies apply to any account, whether an individual account, accounts with financial intermediaries such as investment advisers, broker/dealers or retirement plan administrators, commonly called omnibus accounts, where the intermediary holds fund shares for a number of its customers in one account. The fund’s ability to monitor trading in omnibus accounts may, however, be severely limited due to the lack of access to an individual investor’s trading activity when orders are placed through these types of accounts. There may also be operational and technological limitations on the ability of the fund’s service providers to identify or terminate frequent trading activity within the various types of omnibus accounts. The fund’s distributor has entered into agreements with intermediaries requiring the intermediaries to, among other things, help identify frequent trading activity and to prohibit further purchases or exchanges by a shareholder identified as having engaged in frequent trading. These agreements took effect on October 16, 2007.

The fund’s policies also require personnel such as portfolio managers and investment staff to report any abnormal or otherwise suspicious investment activity, and prohibit short-term trades by such personnel for their own account in mutual funds managed by the manager and its affiliates, other than money market funds. Additionally, the fund has adopted policies and procedures to prevent the selective release of information about its fund holdings, as such information may be used for market-timing and similar abusive practices.

The fund’s policies provide for ongoing assessment of the effectiveness of current policies and surveillance tools, and the Board reserves the right to modify these or adopt additional policies and restrictions in the future. Shareholders should be aware, however, that any surveillance techniques currently employed by the fund or other techniques that may be adopted in the future may not be effective, particularly where the trading takes place through certain types of omnibus accounts. As noted above, if the fund is unable to detect and deter trading abuses, the fund’s performance, and its long-term shareholders, may be harmed. In addition, shareholders may be harmed by the extra costs and portfolio management inefficiencies that result from frequent trading of fund shares, even when the trading is not for abusive purposes. Furthermore, the fund may not apply its policies consistently or uniformly, resulting in the risk that some shareholders may be able to engage in frequent trading while others will bear the costs and effects of that trading. The fund will provide advance notice to shareholders and prospective investors of any specific restrictions on the trading of fund shares that the Board may adopt in the future.

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Share certificates

The fund does not issue share certificates.

Record ownership

If you hold shares through a Service Agent, your Service Agent may establish and maintain your account and be the shareholder of record. In the event that the fund holds a shareholder meeting, your Service Agent, as record holder, will vote your shares in accordance with your instructions. If you do not give your Service Agent voting instructions, your Service Agent may nonetheless, under certain circumstances, be entitled to vote your shares.

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Dividends, distributions and taxes

Dividends and distributions

The fund generally pays dividends, if any, annually, and makes capital gain distributions, if any, twice a year, including one typically in December. The fund may pay additional distributions and dividends at other times if necessary for the fund to avoid a federal tax. The fund expects distributions to be from both income and gains. Long-term capital gain distributions and dividends are reinvested in additional fund shares of the same class you hold. You do not pay a sales charge on reinvested distributions or dividends. Alternatively, you can instruct your Service Agent or Legg Mason Partners Shareholder Services to have your distributions and/or dividends paid in cash. You can change your choice at any time to be effective as of the next distribution or dividend.

Distributions attributable to short-term capital gains are treated as dividends, taxable as ordinary income. Taxable dividends and long-term capital gain distributions are taxable whether received in cash or reinvested in fund shares. Although dividends (including dividends from short-term capital gains) are generally taxable as ordinary income, individual shareholders who satisfy certain holding period and other requirements are taxed on such dividends at long-term capital gain rates to the extent the dividends are attributable to “qualified dividend income” received by the fund for taxable years beginning before January 1, 2011. “Qualified dividend income” generally consists of dividends received from U.S. corporations (other than dividends from tax-exempt organizations and certain dividends from real estate investment trusts and regulated investment companies) and certain foreign corporations.

Long-term capital gain distributions are taxable to you as long-term capital gain regardless of how long you have owned your shares. You may want to avoid buying shares when the fund is about to declare a long-term capital gain distribution or a dividend, because it will be taxable to you even though it may actually be a return of a portion of your investment. A dividend declared by the fund in October, November or December and paid during January of the following year will, in certain circumstances, be treated as paid in December for tax purposes.

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If more than 50% of the fund’s total assets at the end of the taxable year are invested in foreign securities, the fund may elect to pass through to you your pro rata share of foreign taxes paid by the fund, which you must then include in your income and with respect to which you may be entitled to claim a credit (or deduction).

After the end of each year, your Service Agent or the fund will provide you with information about the distributions and dividends you received and any redemptions of shares during the previous year. If you do not provide the fund with your correct taxpayer identification number and any required certifications, you may be subject to back-up withholding at the rate of 28% on your distributions, dividends and redemption proceeds. Because each shareholder’s circumstances are different and special tax rules may apply, you should consult your tax adviser about your investment in the fund.

The above discussion is applicable to shareholders who are U.S. persons. If you are a non-U.S. person, please consult your own tax adviser with respect to the U.S. tax consequences to you of an investment in the fund.

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Share price

You may buy, exchange or redeem shares at their net asset value, plus any applicable sales charge, next determined after receipt of your request in good order, plus any applicable sales charge. The fund’s net asset value per share is the value of its assets minus its liabilities divided by the number of shares outstanding. Net asset value is calculated separately for each class of shares. The fund calculates its net asset value every day the NYSE is open. This calculation is done when regular trading closes on the NYSE (normally 4:00 p.m., Eastern time). The NYSE is closed on certain holidays listed in the SAI.

The Board has approved procedures to be used to value the fund’s securities for the purposes of determining the fund’s net asset value. The valuation of the securities of the fund is determined in good faith by or under the direction of the Board. The Board has delegated certain valuation functions for the fund to the manager.

The fund generally values its securities based on market prices determined at the close of regular trading on the NYSE. The fund’s currency valuations, if any, are done as of when the London Stock Exchange closes, which is usually at 12 noon Eastern time, as the manager believes that these valuations typically reflect the largest trading volume in the foreign currency markets. A material change in the value of currency during the period between the close of the London Stock Exchange and the calculation of the fund’s net asset value on the same date is considered a significant event, as described below, in response to which the fund may use fair valuation procedures to value the affected investments. For equity securities that are traded on an exchange, the market price is usually the closing sale or official closing price on that exchange. In the case of securities not traded on an exchange, or if such closing prices are not otherwise available, the market price is typically determined by independent third party pricing vendors approved by the fund’s Board using a variety of pricing techniques and methodologies. The market price for debt obligations is generally the price supplied by an independent third party pricing service approved by the fund’s board, which may use a matrix, formula or other objective method that takes into consideration market indices, yield curves and other specific adjustments. Short-term debt obligations that will mature in 60 days or less are valued at amortized cost, unless it is determined that using this method would not reflect an investment’s fair value. If vendors are unable to supply a price, or if the price supplied is deemed by the manager to be unreliable, the market price may be determined using quotations received from one or more broker/dealers that make a market in the security. When such prices or quotations are not available, or when the manager believes that they are unreliable, the manager may price securities using fair value procedures approved by the Board. Because the fund may invest in securities of issuers located in emerging markets — some of which may be thinly traded, for which market quotations may not be readily available or may be unreliable — the fund may use fair valuation procedures more frequently than funds that

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invest primarily in securities that are more liquid, such as securities of large capitalization domestic issuers. The fund may also use fair value procedures if the manager determines that a significant event has occurred between the time at which a market price is determined and the time at which the fund’s net asset value is calculated. In particular, the value of foreign securities may be materially affected by events occurring after the close of the market on which they are valued, but before the fund prices its shares. The fund uses a fair value model developed by an independent third party pricing service to price foreign equity securities on days when there is a certain percentage change in the value of a domestic equity security index, as such percentage may be determined by the manager from time to time.

Valuing securities at fair value involves greater reliance on judgment than valuation of securities based on readily available market quotations. A fund that uses fair value to price securities may value those securities higher or lower than another fund using market quotations or its own fair value methodologies to price the same securities. There can be no assurance that the fund could obtain the fair value assigned to a security if it were to sell the security at approximately the time at which the fund determines its net asset value.

International markets may be open on days when U.S. markets are closed and the value of foreign securities owned by the fund could change on days when you cannot buy or redeem shares.

In order to buy, redeem or exchange shares at that day’s price, you must place your order with your Service Agent or the transfer agent before the NYSE closes. If the NYSE closes early, you must place your order prior to the actual closing time.

It is the responsibility of the Service Agents to transmit all orders to buy, exchange or redeem shares to the transfer agent on a timely basis.

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Financial highlights

The financial highlights tables are intended to help you understand the performance of Class A shares for the past five years. Class IS and Class A are invested in the same portfolio of securities. No financial highlights are presented for Class IS shares as the fund commenced the offering of such shares as of the date of this Prospectus. The returns for Class IS shares will differ from those of Class A to the extent that their expenses differ. Certain information reflects financial results for a single share. Total return represents the rate that a shareholder would have earned (or lost) on a fund share assuming reinvestment of all dividends and distributions. The information in the following tables has been derived from the fund’s and the predecessor fund’s financial statements. Except for the financial highlights for the six months ended April 30, 2008, which are unaudited, these financial statements have been audited by                      , an independent registered public accounting firm, whose report, along with the fund’s financial statements, is included in the annual report (available upon request). The financial information shown below for periods prior to April 16, 2007 is that of the fund’s predecessor.

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Legg Mason Partners Funds Privacy Policy

[This page is not part of the prospectus.]

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Legg Mason Partners International All Cap Opportunity Fund

(Investment Company Act

file no. 811-06444)

FD02253 7/08

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PROSPECTUS /JULY     , 2008

Legg Mason Partners

Mid Cap Core Fund

Class IS

The Securities and Exchange Commission has not approved or disapproved these securities or determined whether this prospectus is accurate or complete. Any statement to the contrary is a crime.

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This Prospectus offers Class IS shares of the fund. Class IS shares are sold with no front-end sales charge or contingent deferred sales charge only to Retirement Plans with omnibus accounts held on the books of the fund and Institutional Investors. See “Retirement and institutional investors” for additional information.

As part of a number of initiatives launched in 2006 to restructure and streamline the Legg Mason Partners fund complex, the fund assumed the assets and liabilities of a predecessor fund with the same name, effective April 16, 2007. Any information in this prospectus relating to the fund prior to April 16, 2007 relates to the fund’s predecessor.

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Investments, risks and performance

Investment objective

The fund seeks long-term growth of capital.

Principal investment strategies

Key investments

Under normal circumstances the fund invests at least 80% of the value of its net assets, plus any borrowings for investment purposes, in equities, or other investments with similar economic characteristics, of medium-sized companies. Medium-sized companies are defined as those companies whose market capitalization values are in the range of the market capitalization values of the constituents of the S&P MidCap 400 Index or the Russell Midcap Index, as defined from time to time. Securities of companies whose market capitalizations no longer meet this definition after purchase by the fund still will be considered to be securities of medium capitalization companies for purposes of the fund’s 80% investment policy. As of March 31, 2008, the market capitalization range of the S&P MidCap 400 Index was from $260 million to $12.5 billion, the market capitalization range of the Russell Midcap Index was from $155 million to $45.7 billion.

Equity securities include exchange traded and over-the-counter common stocks, preferred stocks, debt securities convertible into equity securities and warrants and rights relating to equity securities. The fund may also invest up to 25% of its assets in securities of foreign issuers both directly and through depositary receipts for those securities.

Selection process

The fund pursues a disciplined core investment strategy combining in-depth fundamental and quantitative analysis to identify attractive investment candidates. The portfolio managers obtain market information about the universe of investment candidates and distill that information to cull prospective investments. The portfolio managers then establish market-implied growth and return expectations based on current trading price and challenge those expectations using their insight and proprietary analysis. In selecting companies, the portfolio managers consider:

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While markets are relatively efficient in the long term with economic fundamentals driving asset prices, market inefficiencies often occur, as evidenced by the disproportionate volatility of stock prices relative to publicly available information. The portfolio managers believe this disciplined investment process, employing quantitative and fundamental analysis, can help exploit these market inefficiencies.

Principal risks of investing in the fund

Investors could lose money on their investment in the fund, or the fund may not perform as well as other investments, in the event of the following:

Because the fund invests primarily in medium capitalization companies, an investment in the fund may be more volatile and more susceptible to loss than an investment in a fund which invests primarily in large capitalization companies. Medium capitalization companies may have more limited product lines, markets and financial resources than large capitalization companies. They may have shorter operating histories and more erratic businesses, although they generally have more established businesses than small capitalization companies. The prices of medium capitalization stocks tend to be more volatile than the prices of large capitalization stocks.

In addition, the fund is permitted to engage in short sales. Short sales may be considered speculative and involve risk beyond the amount of money used to secure each transaction.

Who may want to invest

The fund may be an appropriate investment if you: