James Corden really knows how to make our holiday dreams come true. Last December, the Late Late Show host decided to give the world the best Christmas present when he debuted a new Carpool Karaoke featuring Mariah Carey. In addition to the legendary singer driving around town with James to help him with his Christmas shopping, the two belt out her classic hit "All I Want For Christmas Is You." But that's not even the best part. A little over 40 seconds into the video, you realize that James got a handful of his Carpool Karaoke guests to sing the song with him throughout the year, resulting in one amazing mashup. Not only does Adele get totally into it, but Lady Gaga, Selena Gomez, Gwen Stefani, Demi Lovato, and "Saint" Nick Jonas also deliver. This video may be from 2016, but it will be the gift that keeps on giving every single year.