Exhibit 99.1 VIACOM STATEMENT REGARDING LAWSUIT TO ENJOIN BLOCKBUSTER SPLIT-OFF EXCHANGE OFFER NEW YORK, NEW YORK, September 20, 2004 - Viacom Inc. (NYSE: VIA, VIA.B) said today that the lawsuit filed on September 17, 2004 in the Court of Chancery of Delaware seeking to enjoin the company's Blockbuster split-off exchange offer is entirely without merit. The suit named Viacom Inc., National Amusements Inc. and each of Viacom's directors as defendants and, among other things, alleges that the related Prospectus-Offer to Exchange omits material information. Information About the Exchange Offer Stockholders of Viacom are advised to read Viacom's Tender Offer Statement on Schedule TO, Blockbuster's Registration Statement on Form S-4 and the Prospectus-Offer to Exchange, as well as any other documents relating to the exchange offer that are filed with the SEC when they become available because they will contain important information. Stockholders of Viacom may obtain copies of these documents for free at the SEC's website at http://www.sec.gov or from Viacom Investor Relations at 1-800-516-4399. Viacom stockholders may also request copies of the exchange offer documents from Viacom's information agent, MacKenzie Partners, Inc., located at 105 Madison Avenue, New York, NY 10016, at (800) 322-2885 (toll-free) in the United States or at (212) 929-5500 (collect) elsewhere. Viacom Contacts: <Table> <Caption> Media: Analysts/Investors: Carl Folta Martin Shea Senior Vice President, Corporate Relations Senior Vice President, Investor Relations (212) 258-6352 (212) 258-6515 carl.folta@viacom.com marty.shea@viacom.com Susan Duffy James Bombassei Vice President, Corporate Relations Vice President, Investor Relations (212) 258-6347 (212) 258-6377 susan.duffy@viacom.com james.bombassei@viacom.com </Table>