Demi Lovato wants Britney Spears to return to 'The X Factor' USA.

The 'Toxic' singer quit as a judge after just one season on the show and Demi is devastated she won't be working with Britney again, although she has come up with a suitable replacement.

She told Us Weekly: ''I wish Britney would come back. My next pick is Lady GaGa though, she's so cool.''

Demi and Simon Cowell are the only remaining members of the panel after L.A. Reid also quit at the end of last season, and the TV mogul says top of his list for the new panel is chemistry between the judges.

A source said: ''Simon delivered a simple message: Forget the big names and go for chemistry. He said all these shows have become distracted by signing celebrities rather than judges who really have something to say. We have all seen that big names don't translate into big ratings.

''Chemistry is top of the list of demands for next season. [Only Demi will return because her chemistry with Simon was] the best thing about the panel last year.''

Both Jennifer Love-Hewitt and Kelly Rowland have been rumoured as possible replacements to join the panel in 2014.