Britney Spears has officially signed on to become part of the X Factor USA judges' panel.

Following weeks of reports that the Toxic singer would be joining the hit reality singing show, E! News has officially confirmed to fans that Ms Spears has signed a contract.

A source close to the singer told the website: "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.

"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 will reportedly receive $15 million for the season.

Earlier this month, it was suggested that Demi Lovato will fill the fourth role at the X Factor USA judges' table. However, this is yet to be confirmed.