Adele to sing on X Factor Final?

Simon Cowell has said he hopes that Adele will be able to perform during the final of the UK X Factor and that she'll make an appearance on the US version as well. An insider says: "There's no denying Adele is the biggest singer in the world right now and Simon wants her to appear on both the UK and US X Factors. He couldn't get her for the Judges' Houses stage, so he now wants her to sing with one of the contestants on the grand final in December. She is a massive fan of the show and even went to watch the US X Factor auditions earlier this year."