Rumor has it that the already seriously skinny Angelina Jolie has put herself on a liquid only diet, which has sparked concern on the set of her latest film, Salt.

According to the U.K.'s The Sun, the actress, and mother of six, is trying to lose 21-pounds in 21 days for her role as a Russian spy in the film. A source told The Sun: "She does all her own stunts, but we worry she could injure herself due to the weight loss."

The actress is said to be using the same diet Beyonce used to lose 20-pounds. Called, the "Master Cleanse," the liquid diet is supposed to shed pounds fast and detox your body.

The diet involves only drinking a mixture of water, lemon juice, cayenne pepper and maple syrup for around two weeks.

Beyonce told People that although she lost the weight, she wouldn't recommend it:

"It was a liquid diet where you lose weight really fast. I would not recommend it if someone wasn't doing a movie, because there are other ways to lose weight. But I needed to lose it really quick, and I put the weight back on as soon as I finished, so I am no smaller or bigger than I've always been."

Source: http://www.zimbio.com/Angelina+Jolie/articles/3065/Angelina+Jolie+Tries+New+Liquid+Diet