Nick Jonas, who's in the band 'Jonas Brothers', will join Demi Lovato (New X Factor USA judge) in the judges homes stage of the competition. The category Demi has are the 12-16's.
Justin Bieber will join LA Reid to mentor .. wait for it .. the OVERS category!! How can that work?! Justin's a teen himself..
As for who is joining Britney and Simon, that hasn't been revealed yet. But so far, regardless of who they'll be mentoring.. nick and justin are quite big names. So I'm guessing Simon and Britney will have even bigger names.. which will be good!
Can't wait for the x factor usa!