Demi Lovato Is In 'Good Shape' On 'X Factor,' Nick Jonas Teases

'She has an incredible ear for music,' singer tells MTV News about his pal, ahead of Wednesday night's mentoring episode.

EAST RUTHERFORD, New JerseyDemi Lovato is getting a little help from her friend, Nick Jonas, on the "X Factor" Wednesday night (October 10). Once the Boot Camp sessions come to a close, the contestants will then be shipped off to spend some quality time with their respective judge and a special, hand-picked mentor.

Lovato asked her "Camp Rock" co-star and former tourmate to help her whip the contestants into shape. And, Jonas tells MTV News he didn't let anyone get away with anything.

"I was really honest. I don't know if I was too honest or not, but I know that it was great to work with Demi on that," he shared in between rehearsals at the Izod Center, where he had been prepping for the Jonas Brothers' big comeback show at Radio City on Thursday night. Jonas had been rumored for the "X Factor" gig back in August.

He continued, "And we have a really great friendship and have now for a long time and doing something like that, working together to help her, cause at the end of the day it was her decision of who goes on to the next round, it was great to sit with her. And, [to] help her make up her mind cause it's a lot of pressure."

Jonas won't be the only A-lister helping out. L.A. Reid will be joined by Justin Bieber, will aid Britney Spears and Simon Cowell will work with Marc Anthony. Once the contestants are narrowed down to 24, each judge is assigned to one of the brand-new season two categories (like last year's men, women, over 30 and groups), after which the remaining contestants will find out who their mentors are. And, Nick thinks Lovato has a certain edge that makes her one of the best on the panel.

"I think she's great as a judge," he said. "I think she has an incredible ear for music. I know that over time, I love and have loved writing music with her. Also being able to tell what works for an individual with the 'X Factor,' it's not just about the voice or the performance; it's about the whole package. And she's got a pretty good eye for that and great ear as well. So, she's in good shape."