VIDEO: Simon Cowell, Demi Lovato, Britney Spears and their guest mentors talking at the Judges Houses on TheXFactorUSA

The teams break down like this: Nick Jonas with Demi Lovato, Will.i.am with Britney Spears, Marc Anthony with Simon Cowell and Justin Bieber with L.A. Reid.

 Simon Cowell called this round one of his favorites because "this is where you get to separate from the other three judges. You're one-on-one. You're in much more control of the situation. You're choosing the material. You're in very close proximity to the artist and you get to know more about them."

"We've seen a lot of life together at this point," Nick Jonas said of his relationship with Demi Lovato. "One thing I specifically remember about Demi is that when we'd be on stage together, we could look at each other from across the stage and kind of know exactly what the other person was thinking."

"We get each other," Marc Anthony said of his friendship with Simon Cowell. He went on to joke, "It's a really weird, bizarre relationship, because I don't even know why I like him."