Paul McCartney joined Jimmy Fallon and the cast of the animated film 'Sing' for an excellent a cappella rendition of his 1979 holiday hit 'Wonderful Christmastime'. The video was aired on 'The Tonight Show' featuring each musician singing along in the usual 3 by 3 coloured boxes.

Paul McCartneyPaul McCartney does 'Wonderful Christmastime' a cappella

To celebrate the holidays, Jimmy Fallon unveiled an a cappella Christmas special for his talk show. House band The Roots featuring Questlove took on the instrumental mimickry while the cast of 'Sing' - them being Reese Witherspoon, Scarlett Johansson, Matthew McConaughey, Seth MacFarlane and Tori Kelly - sang the vocals, joined by Fallon and Sir Paul himself. We also got a glimpse of the CGI characters from the movie singing along.

'Sing' hit theatres this week (December 21st 2016). It's an animated comedy directed by Christophe Lourdelet in his directorial debut and Garth Jennings ('The Hitchhiker's Guide to the Galaxy', 'Son of Rambow'), and written by the latter, and follows the story of a koala who wants to save his theatre by opening a singing competition for all the talent of the anthropomorphic animal city.

The film is currently up for two Golden Globes; Best Animated Motion Picture and Best Original Song for 'Faith' performed by Stevie Wonder and Ariana Grande; and it also stars Taron Egerton, Jennifer Saunders, Jennifer Hudson and Leslie Jones. The soundtrack also features a couple of tributes to stars who have died this year, Leonard Cohen's 'Hallelujah' and Queen's 'Under Pressure' featuring David Bowie.

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The a cappella spot is a regular segment on 'The Tonight Show'; previous guests have included the cast of 'Star Wars: The Force Awakens' for a wordless medley of the series score, and such vocal heroes as Carrie Underwood, Sam Smith, Ariana Grande, One Direction and Christina Aguilera for a rendition of Queen's 'We Are The Champions'.