Tom Cruise, Cameron Diaz, Julia Roberts and Will Smith are the latest addition of stars set to join Tom Hanks, George Clooney, Jim Carrey and Bruce Springsteen on the unprecedented TV telethon, the two-hour, commercial-free "America: A Tribute to Heroes," this Friday. ABC, CBS, NBC and Fox will ALL telecast the program, and the WB and UPN are expected to announce on Wednesday that they, too, will pre-empt programming to air the special, reports Variety. A large contingent of cable networks will also air the show, which will be broadcast from both New York and L.A. So far, they are Lifetime, E!, FX, MTV, SoapNet, National Geographic Channel and Fox Movie Channel, as well as Spanish language outlet Telemundo. Other cable channels, including TNT and USA, are also expected to decide on Wednesday whether or not to participate. Also joining the special are Bon Jovi, Sheryl Crow, Dixie Chicks, Robert De Niro, Clint Eastwood, Faith Hill, Billy Joel, Alicia Keys, Tom Petty, Paul Simon, Robin Williams, Stevie Wonder and Neil Young. The Big Four networks will also supply two stars each: appearing from CBS will be Amy Brenneman and Ray Romano; from ABC, Dennis Franz and Sela Ward; from NBC, Kelsey Grammer and Conan O'Brien; and from Fox, Calista Flockhart and Jane Kaczmarek, says the trade paper. The Big Four will underwrite the show's costs, and all money raised will go toward relief efforts relating to last week's attacks.