Britney Diets for X Factor?

Britney Spears is on a crash diet ahead of her performance on The X Factor, and is hoping to shift half a stone, according to reports.

The pop singer has already lost two stone since her public meltdown, but wants to be super-slim before the show this weekend, according to the Daily Star.

Britney, 26, was pictured at Los Angeles airport yesterday, about to board a flight to the UK.

The mother-of-two is a close friend of X Factor choreographer Brian Friedman, who was behind the dance moves for some of her biggest hits.

A source told the paper: "She goes to bed hungry and is dieting so hard she's suffering from insomnia, anxiety, flushes and shakes.

"Her father and the people around her are trying to get her to eat more, but Britney is determined not to be criticised for having any extra bulk."