Britney SpearsThe thought of performing in front of Simon Cowell is clearly freaking Britney Spears out.

It seems that Brit is going to crazy lengths to prepare herself for her stint on The X Factor this weekend.

It'll be her first British performance in five years but it seems that the issue of weight is what is concerning her the most.

The singer has apparently been crash-dieting in a bid to shed some extra pounds.

The Daily Mail have reported that Brit wants to lose up to seven pounds, before the much anticipated show this Saturday.

"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," a source told the paper.

Rest easy, Britney, that is not going to happen.

We can already see that Britney has lost a load of weight since getting her life back on track this summer.

And the singer cut a very svelte figure at LAX airport on Monday as she headed to Britain - any thinner and we'd worry.

It's fair to say that the hype surrounding the performance of Britney doing Womanizer this weekend is enormous.

Brit will also be reunited with her former choreographer, Brian Friedman, who is the creative director on The X Factor.

"She is such a sweet, endearing person. It will be nice to reconnect," he said to the Daily Mail. "I'm so glad to see her back on track. Her performance is going to be incredible."