Jessica Biel's strip contract

Jessica Biel has agreed to bare her breasts and butt in her new movie.

The 25-year-old sex symbol - who plays a stripper trying to earn money to care for her terminally ill son in 'Powder Blue' - has signed a contract stating she will reveal the specific body parts after initially being reluctant to strip off.

A source told Us Weekly magazine: "Jessica signed a contract that explicitly details the bare minimum fans will see - including shots of her breasts and butt."

Jessica - who stars alongside Oscar winner Forest Whitaker in the movie - recently confessed she is worried about her dad and brother seeing her naked on screen.

She said: "I definitely worry about how my family would react. You can't help thinking about your dad or brother seeing something.

"I don't have to be fully naked for the movie. I haven't decided exactly about the nudity. It's a tough one. I'm considering it but it's a very scary thing to do.

"It definitely feels vulnerable to be naked in front of anybody, let alone a film crew.

"And it's scary because of the internet - you don't know where it's going to end up. It's a moment that could be exploited."

'The Illusionist' star - who was rated number one in Stuff magazine's 100 Sexiest Women 2007 list - is currently dating pop heartthrob Justin Timberlake.