The US popstar will perform her new single 'Womanizer' on the ITV talent show. It will be her first visit to the UK since 2004.
Cowell is quoted by WENN as saying: "We have the number one show in England. It's the best show for her to perform on. We're absolutely thrilled to have her.
"Everyone wants to work with her because she's a star. She's the number one booking in the world at the moment for a show... The fact that she goes a bit crazy occasionally makes her more interesting.
"And, if she wants to shave her head before she comes on the show, she's welcome to. I don't care."