Spears for X-rated 'X Factor' performance?

Rex Featues

Tabloid reports have claimed that Britney Spears is planning an X-rated performance for this week's X Factor.

The American popstar is attempting to lose half a stone and "sex up her act", according to the Daily Star.

Spears is determined to "outshine" the show's judges Cheryl Cole and Dannii Minogue and has allegedly resorted to extreme dieting to ensure that there are no comments about her weight.

"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," said a source.

Spears releases her new album Circus on December 1.