Has Brad Pitt lost his mind?

In an interview with Entertainment Weekly, Brad Pitt said he kept himself and his co-stars entertained on the set of his movie Babel but giving himself wedgies and walking around like a duck.

No, I'm not making this up.

"Cate (Blanchett) called it the Hungry Bum. When your bum's so hungry it's trying to eat your pants."

I think he needs to spend a bit of "me" time - perhaps without the children? He seems to be picking up his 6 year old's habits.