What is carpool karaoke, you ask? Well, it's when you pick someone up to join you on your ride to work, but all they do is sing. It's the best way to deal with Los Angeles traffic, according to Corden. Probably even better when you have Mariah as your co-pilot.

Because Corden doesn't know how to change the radio in his Range Rover, so he says, Mariah's "Always Be My Baby" comes on and the two can't help but join in. It's like Mariah in surround sound.

Soon they're performing "Fantasy," with Corden taking on Ol' Dirty Bastard's part. His dance moves are really what make this even better. And he's not so bad at hitting some of those high notes, by the way.