Brad's levity brightens movie set

Brad Pitt

Brad Pitt found a way to blow off steam and bring some levity to the set of his new movie, Babel.

The 42-year-old actor says he amused himself and co-stars by yanking up his pants, sticking out his rear and waddling about like a duck.

"Throughout the movie, I'd walk around like this," he says. "You've gotta find things to make you laugh during the shoot. Cate [Blanchett] called it the Hungry Bum - when your bum's so hungry it's trying to eat your pants."