James Corden’s carpool karaoke is just the gift that keeps on giving. Realizing at some point that this would be a recurring bit, he decided to do an extra-special Christmas version, with each of his guests singing “Joy to the World,†including Justin Bieber, One Direction, Iggy Azalea, Stevie Wonder, Rod Stewart, Carrie Underwood, and more! (Unfortunately, he probably got the idea after Jennifer Hudson came on, which is too bad because she obviously would have slayed this reindeer song to high heaven.) Merry Christmas!