James Corden's Carpool Karaoke has quickly become one of the best bits on late-night television, and it continues to get better. The crew is in the Christmas spirit in the latest episode, with a full cast of celebrities from Justin Bieber, One Direction, and Stevie Wonder singing "Joy to the World" while riding around with Corden. Not only that, but Iggy Azalea decided to spit a little holiday freestyle that was interesting, to say the least. Regardless, the full video will have you out caroling with your family in no time.