In November 2011, Carey re-recorded the song as duet with John Legend, which was later released that month as a standalone single by Island Records.

The song's accompanying music video features Carey and Legend hosting a Christmas house party.

[3] The instrumental consists of horns, including the trumpet performed by Rick Baptist and Greg Adams, and the trombone by Nick Lane.

"[6] In an interview for Vevo, Carey stated that she felt that Legend was the "perfect choice" to re-create the song as a duet with, and that his "soulful" creative decisions "took it up several notches".

[8] Mike Diver for BBC was complimentary of "When Christmas Comes", writing although the effect is "less instant" compared to the first single, "Oh Santa!

[9] The Village Voice writer Rich Juzwiak thought that the use of a full band was a "retread" of the songs Carey recorded for her tenth studio album, The Emancipation of Mimi (2005).

[10] Of the duet, Shelter described it as "sultry", awarded it four stars out of a possible five, and labelled it as being superior to the original version with vocals solely by Carey included on the album.

[23] On November 15, Carey posted images of the video shoot on her website, one of which shows the two singers sitting at piano.