Once Ben Stiller landed one of the most sought after yet beguiling roles in Hollywood, why not direct himself, too?Twitchfilm.com reports that Stiller will not only star in the big screen adaptation of the classic 1939 James Thurber short story, "The Secret Life of Walter Mitty," -- he signed on in April -- he'll helm it from behind the camera, too.This will be Stiller's fourth directorial effort, after "Reality Bites," "The Cable Guy," "Zoolander" and "Tropic Thunder," and in a way, his first remake: the story was originally made into a film back in 1947.Read More... More on Celebrities