Mariah Carey and James Corden just gave everyone the best Christmas surprise.
The singer started off a Carpool Karaoke with Corden but what we weren't expecting was what came after. This version of this now famous segment turned into a star-studded sing-along of Carey's "All I Want for Christmas is You" with some of the celebrities that did Carpool Karaoke this in 2016. Some of the stars that made an appearance were Selena Gomez, Demi Lovato, Elton John, Nick Jonas, Lady Gaga and more.
Check out what other stars made an appearance in the video above!