Darsteller
Keanu Reeves (Klaatu), Jennifer Connelly (Dr. Helen Benson), Kathy Bates (Regina Jackson), Jon Hamm (Dr. Granier), Jaden Smith (Jacob Benson), John Cleese (Prof. Barnhardt), Juan Riedinger (William), Will Smith (Capt. Steven Hiller), Bill Pullman (President Thomas J. Whitmore), Jeff Goldblum (David Levinson), Mary McDonnell (Marilyn Whitmore), Judd Hirsch (Julius Levinson), Margaret Colin (Constance Spano), Randy Quaid (Russell Casse), Robert Loggia (Gen. William Grey), James Rebhorn (Albert Nimziki), Harvey Fierstein (Marty Gilbert), Adam Baldwin, Brent Spiner, James Duval, Vivica A. Fox, Lisa Jakub, Ross Elliot Bagley, Mae Whitman, Bill Smitrovich, Kiersten Warren, Harry Connick jr., Dennis Quaid (Jack Hall), Jake Gyllenhaal (Sam Hall), Emmy Rossum (Laura Chapman), Dash Mihok (Jason Evans), Jay O. Sanders (Frank Harris), Sela Ward (Dr. Lucy Hall), Austin Nichols (J.D.), Arjay Smith (Brian Parks), Tamlyn Tomita (Janet Tokada), Sasha Roiz (Parker), Sir Ian Holm (Terry Rapson), Nassim Sharara (Saudischer Delegierter), Carl Alacchi (Venezuelischer Delegierter), Kenneth Welsh (Vizepräsident Becker), Michael A. Samah (Saudischer Übersetzer), Robin Wilcock (Tony), Jason Blicker (Paul), Kenneth Moskow (Bob), Tim Hamaguchi (Taka), Glenn Plummer (Luther), Adrian Lester (Simon), Richard McMillan (Dennis), Nestor Serrano (Gomez), Sylvain Landry (Wissenschaftsoffizier), Chris Britton (Vorsteen), Vlasta Vrana (Booker (MPC)), Pauline Little (Lanson), Alan Fawcett (Commander Daniels)