The gala is to take place Monday night at Grauman's Chinese theater.
Expected to attend are director and star Clooney, as well as his fellow cast members Renee Zellweger, John Krasinski, Jonathan Pryce, Stephen Root, Wayne Duvall, Keith Loneker, Robert Baker, Malcolm Goodwin, Tim Griffin, Tommy Hinkley, Nick Paonessa, Mike O'Malley and Nicholas Bourdages.
Also on the guest list are writers Duncan Brantley and Rick Reilly, producers Grant Heslov and Casey Silver, and Krasinski's co-stars from the TV sit-com "The Office" -- Brian Baumgartner, Jenna Fischer, Angela Kinsey, B.J. Novak and Rainn Wilson.
Set in the 1920s, the football flick is to open in U.S. theaters April 4.