It's finally here! The music video for Justin Bieber's Christmas duet with Mariah Carey, "All I Want For Christmas Is You" has hit the web, and it looks like Mariah didn't want to let the Biebs steal the show, as she nearly upstaged him with her super sexy Santa costume!

Mariah previously released her cover of the same song back in 1994, and we can't think of a better way to re-vamp the tune than to show off her hot post-baby bod and include Justin. The new version appears on Bieber's Christmas album Under the Mistletoe, but it seems like he isn't exactly a pro when it comes to belting out Christmas songs. During an appearance on The Today Show last week, Bieber messed up the lyrics to "Santa Claus is Coming To Town", covering up his blunder by singing the same line several times before dancing around. Looks like he pulled one straight from the book of Ashlee Simpson!