AceShowbiz -

To celebrate the movie's upcoming release as well as Christmas, the cast of "Sing", Reese Witherspoon, Matthew McConaughey, Scarlett Johansson, Tori Kelly and Seth MacFarlane, teamed up with Jimmy Fallon for an a capella rendition of Paul McCartney's "Wonderful Christmastime". A clip of their collaboration was aired on Tuesday night, December 20 on "The Tonight Show Starring Jimmy Fallon".

Joining house band The Roots, the cast members and Fallon added their voices to the Christmas classic. In the beginning of the clip, the late-night TV host and his house band create a seamless blend of sound. Witherspoon and Johansson then join Fallon, singing, "The mood is right/ The spirits up/ We're here tonight/ And that's enough/ Simply having a wonderful Christmas time."

Kelly joins McConaughey, Johansson and Fallon, singing, "The choir of children sing their song/ They practiced all year long/ Ding dong, ding dong/ Ding dong, ding dong." Towards the end of the clip, McCartney enters the frame, singing, "We're here tonight/ And that's enough/ Simply having a wonderful Christmas time/ Simply having a wonderful Christmas time." The clip also features some characters in the movie, including koala Buster Moon, mouse Mike, Indian elephant Meena, green iguana Karen Crawly, domestic pigs Rosita and Norman, porcupine Ash and a snail.

Written and directed by Garth Jennings, "Sing" follows Buster Moon (Matthew McConaughey) who tries to produce the world's greatest singing competition. The animated comedy flick is set for a December 21 release in U.S. theaters.