Brad Pitt amused his co-stars on the set of new movie 'Babel' with his underwear antics.
The 'Ocean's Thirteen' star regularly made his co-stars smile by yanking his underwear above the waist of his trousers and "waddling about like a duck".
Brad, 42, revealed: "Throughout the movie, I'd walk around like that. You've got to find things to make you laugh during the shoot. Cate Blanchett called it the 'Hungry Butt'."
When Brad was asked explain the 'Hungry Butt' he revealed to Entertainment Weekly: "It's when your butt's so hungry it's trying to eat your pants."
However, despite his japes, Brad - who is the adoptive father of his partner Angelina Jolie's children, five-year-old Maddox from Cambodia and 18-month-old Zahara, from Ethiopia - said he felt a very personal connection with 'Babel', which is about several families linked by a tragedy in the African desert.
He said: "Our kids come from different parts of the world, and it's the perfect example of if we didn't have these perceived differences we wouldn't be defined by geography.
"What I liked most about the script was the idea that we're all the same, and it's our lack of understanding and communication that gets in the way."
Gwyneth Paltrow was reduced to tears by Brad Pitt's latest movie, 'Babel'.
The mother-of-two - who onced dated the actor - was overcome with emotion at
the Cinema Society screening of the movie in New York earlier this week.
Gwyneth, who is married to Coldplay frontman Chris Martin, gushed to the New
York Daily News newspaper: "It's the best performance Brad's ever given.
"It makes you want to take good care of your children."
The Oscar-winning actress was so moved by the film she ditched the film's
after-party to head straight home to her two children, Apple and Moses.
'Babel' - which opens in the US this weekend and will close the London Film
Festival on November 2 - is about several families linked by a tragedy in
the African desert.
Meanwhile, another of Brad's ex lovers, Jennifer Aniston, is to star
alongside Gwyneth in a new film.
The pair are reportedly planning to co-star in a new thriller - with Aniston
playing the villain.
The 'Friends' actress was married to the 'Troy' star for four years before
they divorced last year, while Gwyneth's engagement to the handsome actor
ended in 1997.
Brad is now dating 'Tomb Raider' actress Angelina Jolie.