Angelina Jolie is reportedly battling fatigue as she tries to lose weight for her new film 'Salt'.
The 33-year-old actress is reportedly trying to lose 21lbs in 21 days for an upcoming film in which she plays a CIA assassin who is forced to disguise herself as a man.
Friends claim Angelina is so determined to look like a boy she has turned to the Martha's Vineyard Detox Diet to help shrink her frame.
The extreme diet - which was popular in Hollywood in 2007 - encourages followers to ingest liquids every two hours to 'cleanse the body'. Solid food is strictly prohibited.
Angelina reportedly started her detox three days before last month's Oscars and is already battling weakness and fatigue.
A source told Britain's Grazia magazine: "She has been trying to go for the full 21 days but it's tough. She's lost around eight pounds but is now introducing a couple of small meals in between shakes as she was starting to feel weak."
Angelina's partner Brad Pitt is reportedly so fed up with her new diet he stormed out of their rented Long Island mansion last week.
A friend said: "Brad told her that if she was staying on the diet, he was getting out of the way. Then she started screaming at him about a chore. 'He felt that what he did or said would be wrong, so he went to Los Angeles to let off steam with some buddies."
