Britney Spears has officially signed up to US 'X Factor'.

The Toxic one has reportedly penned a $15 million deal to be a judge on the talent show alongside Simon Cowell and L.A. Reid after months of negotiations.

A source close to the 30-year-old singer (cause she doesn't speak herself any more) told E!: "The contract is signed. There's been a lot of back and forth over the past few weeks as they negotiated the small details, but she's on. It's all completed and Britney is beyond excited."

Her appointment comes after Simon fired former panellists Paula Abdul and Nicole Scherzinger, as well as host Steve Jones, earlier this year following the end of the show's inaugural season - and he didn't get the 20 million viewers he said he'd get.

Again, Britney is said to be 'excited' about working with the music mogul, who has previously declared he would (percentile alert) "100 per cent" sign her up for the show given the chance.

The insider added: "She's ready for this. She can't wait to sit down next to Simon at the judges' table and give this everything she's got. She is excited about showing the world that she can do this, and do this well. This is the perfect next stage in her career. Both Britney and Simon are very excited to work together." As is Jamie Spears, who's still looking after the money side of things. 

So, who's going to be perched between Britney and L.A. Reid (as it's been made pretty clear that Britney's sitting beside Simon)... rumours has it that Britney is championing Demi Lovato. Makes sense, they have a lot in common.