James Corden has topped a year of splendid Carpool Karaoke sessions with a Christmas special that looks as though it's been in the works since January.

The Late Late Show host posted the video with Mariah Carey as his guest passenger for an all-star rendition of her hit song 'All I Want for Christmas'.

The video also features Adele, Coldplay's Chris Martin, Elton John, Nick Jonas, Demi Lovato, Red Hot Chili Peppers, Gwen Stefani and Selena Gomez.

"Thank you so much for helping me with my Christmas shopping," Corden begins in the video. "What would be the best gift... what would you want this Christmas?"

We know where this is going.

"I want you to sing my song 'All I Want for Christmas is You," Carey replies.

'All I Want for Christmas is You' is one of Britain's most popular Christmas songs. It was in the top three most-streamed Christmas songs on Spotify in 2015 (with The Pogues and Kirsty MacColl's 'Fairytale of New York' and Wham!'s 'Last Christmas'