Liv Tyler exposed bum on 'Hulk' set

Liv Tyler repeatedly exposed her bum to cast and crew during filming on The Incredible Hulk.

According to director Louis Leterrier, Tyler's pants were so tight in the film that they kept tearing and exposing her rear.

"I have a secret for you - it didn’t happen on one occasion, it happened on several occasions where Liv’s pants tore open," he told Fox News.

Tyler's repeated mishaps apparently earned her the nickname "Action Pants".

"She definitely deserves her nickname," said Leterrier. "Her pants were very thin, but I love to put my actors in the real action, the real deal."