Mariah Carey [photos] is the surprise singer Justin Bieber had been promising for his upcoming Christmas album.
The new mom made the reveal on Tuesday and said she re-recorded her classic 'All I Want for Christmas' with Bieber for the album.
"I am here today to tell you a little secret," Carey says in a video for the announcement.
"Justin and I are doing this little duet together. I'm very excited about it. I think a lot of you are already very surprised by this and you're going to be even more surprised when you hear it."
"The song sounds great. I'm very excited for everybody for this Christmas to be totally festive with out collaboration."
Usher, Band Perry, Busta Rhymes, Boyz II Men are some of the other names contributing to the album called 'Under the Mistletoe'.
The first single from Bieber's album will drop October 18, with the album due November 1.
