Mariah Carey and R. Kelly

Watch Mariah Carey & R. Kelly Perform ‘The Christmas Song’

Mariah Carey and R. Kelly know how to get in the holiday spirit.

Teaming up for a special performance at the Beacon Theatre in New York on Thursday (Dec. 8) as part of Mimi’s third annual “All I Want for Christmas Is You” celebration, MC and The R celebrated the season with Nat King Cole’s classic “The Christmas Song.”

“We’ve never done this before,” Mariah told the audience, before explaining her nervousness. “I want to do this song and I’ve never done it before so I’m a little nervous, especially because this is one of my favorite singers right here,” she added, pointing at Kellz.

There was, of course, no need to fret. Soon, Mariah and the Pied Piper were dazzling the audience with vocal prowess, before toasting to the holidays with eggnog. Kelly, who just released his holiday album 12 Nights of Christmas, ended the performance by planting a series of kisses on Mariah’s cheek.

“@rkelly graced my show this holiday season as we performed our mutual favorite Christmas classic ‘The Christmas Song,’ by Nat King Cole,” Mariah wrote on Instagram. “#ThankYouKellz !!! You’re the best!!!” Meanwhile, Kelly said he “had a blast.”

Mariah’s “All I Want for Christmas Is You” shows are full of surprises. Earlier in the week, John Legend joined her for “When Christmas Comes.” And she isn’t done. The show is set to run through Dec. 17.

She also spread holiday cheer on “VH1 Divas Holiday: Unsilent Night,” alongside fellow divas Chaka Khan, JoJo, and Teyana Taylor.