Mariah Carey is said to be gearing up for a performance on one of this years live X Factor shows.

A show insider told The Daily Star: “It is almost done and dusted and they are finalising a date and some of the fine print.

“As always with Mariah there are a few clauses that need to be agreed on and a fuss will have to be made over her.

“Once she heard that Britney Spears was doing it she knew it was the show for her.”

Also rumoured to be appearing on the show are Britney Spears, Girls Aloud, Leon Jackson and Boyzone.