Britney Spears has signed up for the American version of The X Factor.

The Hold It Against Me pop icon reportedly penned a deal worth $15-million (R120-million) for one season's work as a judge on the reality talent show alongside Simon Cowell and LA Reid.

A source told E! News: "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."

The confirmation comes after months of rumours of Spears' possible involvement on the judging panel – spurred on by Cowell's comment that he would "100 percent" sign the singer on if he could.

The source also revealed that Spears is "excited" about the new venture, adding "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."

Spears' appointment comes after Cowell dumped former judges Paula Abdul and Nicole Scherzinger from the panel, and fired host Steve Jones, earlier this year at the end of the show's debut season.