(Trailer can be downloaded)

Ben Stiller says "Tropic Thunder" is a "a comedy about five actors who go on location and find themselves relying on their boot camp experiences when they get stuck in a real war-like situation."

Black will play Jeff "Fats" Portnoy, an overweight gross-out comedian, who's forced to kick his drug addiction while filming on location in the jungle.

Downey Jr. will play Kirk Lazarus, the greatest actor of his generation and a four-time Oscar winner. Baruchel will play Kevin Sandusky, an unknown actor on the set and Stiller plays Speedman.