The X Factor USA: Judges Houses Pictures Revealed
Justin Bieber and manager among guest mentors on reality show...
Fox has not yet released a pic of the fourth judge, Britney Spears, with her guest mentor Will.I.Am.
In a statement from Fox, Jonas said: "I'm lucky to have some incredible mentors in my life and I've always valued their opinions greatly. Being able to provide guidance for another artist, while working with the incredibly talented X Factor team, was an amazing experience.
"There's some extraordinary talent out there, and I couldn't be more thrilled to be a part of their journey."
And Will.I.Am said: "When Britney asked me to come help mentor talent in the Judges' Homes round, it was an easy yes. Some of the talent I've seen so far has blown me away - they're out-of-this-world good."
The X Factor USA's top 24 contestants are to be revealed tomorrow - and will then be whittled down by the judges and their special guest helpers.
Demi Lovato is reported to be sort-of dating Niall Horan from One Direction.