Justin Bieber & Mariah Carey Duet: Listen to Leaked 'All I Want For Christmas'

Justin Bieber & Mariah Carey Duet: Listen to Leaked 'All I Want For Christmas'

In the latest issue of Billboard, Justin Bieber's manager, Scooter Braun, boasts that, "vocally, his balls have dropped." Well, that much is clear on the just-leaked collaborations from Bieber's upcoming Christmas album, "Under the Mistletoe."

Justin Bieber: The Billboard Cover Story

A bass-ier Bieber duets (and scats) with the Christmas queen herself, Mariah Carey, on a remake of her own wintery smash hit, "All I Want For Christmas Is You," which sat atop Billboard's Holiday Songs chart last year. Listen below.

PHOTO GALLERY: Justin Bieber's Fashion Evolution

Another holiday favorite gets the celeb duet treatment on "Under the Mistletoe": "Little Drummer Boy" gets Busta-fied, with a deep-voiced Bieber trading rhymes with Mr. Rhymes. Listen to the carol turned club banger below.

What do you think of Bieber's Christmas covers? Better than the originals? Tell us in the comments below!