The Hangover star Galifianakis will be presented with the Comedy Actor Award, while Bonham Carter and Rockwell have been named Best Supporting Actor and Actress.
The Breakthrough awards go to Hollywood's new Spider-Man Garfield and Alice In Wonderland star Mia Wasikowska, while Oscar-winning director Danny Boyle will pick up a producer prize.
Previously announced honorees include Sean Penn, who will be honoured for his humanitarian work, and Sylvester Stallone, who has landed the Career Achievement prize.
Morgan Freeman will be named best innovator, while Annette Bening and Robert Duvall take the top acting trophies.
The awards will be handed out at a ceremony in Beverly Hills on 25 October (10).