Ben Stiller, Jack Black and Robert Downey, Jr., helicoptered into Camp Pendleton, loaded into military humvees and treated Marines and sailors to an advance screening of their film Tropic Thunder. Walking down a combat green carpet, the trio shook hands with troops, posed for pictures and introduced their new action comedy.

"We were really excited to show this movie to the military personnel who do so much for our country," says Ben Stiller. "I think they really got a kick out of seeing a bunch of spoiled actors complaining about how hard it is to do a war movie. But seriously, it was really hard. We almost did a boot camp, but then decided on a cast dinner instead."

The film is about a group of self-absorbed actors who set out to make the biggest war film ever. After ballooning costs (and the out of control egos of the pampered cast) threaten to shut down the movie, the frustrated director refuses to stop shooting, leading his cast deep into the jungles of Southeast Asia for "increased realism," where they inadvertently encounter real bad guys.

Tropic Thunder will be released nationwide on August 13th.