James Corden has treated us to some seriously awesome Carpool Karaoke videos this year; think Michelle Obama, Adele, Gwen Stefani, Lady Gaga, Sia, and Jennifer Hudson, to name just a few.

But he’s well and truly outdone himself with his latest extra-special Christmassy version of the show.

The clip begins with Corden driving along a wintry road in America, with a Christmas tree tied to the top of his car. It soon becomes apparent that he’s not alone, however, as Mariah Carey – aka the Queen of Christmas herself – is sat right alongside him.

Read more: Stylist goes behind-the-scenes at James Corden's Carpool Karaoke

After thanking Carey for helping him out with his festive shopping, Corden then asks the mega-star if there’s anything she wants for Christmas. Surprisingly shy and retiring, Carey refuses to give him an answer, but the Gavin and Stacey star continues to press her until she tells him her yuletide wish.

“I want you to sing my song, All I Want For Christmas,” she says.

Naturally, Corden is all too happy to comply, and the pair joyfully burst into the iconic Christmassy tune together. Which is incredible, all by itself… only then something even more magical happens.

Adele, please enter the arena.

That’s right; it seems as if Corden has been prepping this festive clip for a very long time, as plenty of his past star guests appear in the fun montage.

After Adele does her best to upstage Carey with her own power-house vocals, Demi Lovato and Nick Jonas are shown jamming out to the fun tune.

They’re swiftly followed by the likes of Sir Elton John, Selena Gomez, Lady Gaga, Gwen Stefani, and Chris Martin.

Read more: Britney Spears and James Corden rock out to Toxic on Carpool Karaoke

Even the Red Hot Chilli Peppers get involved in the pop-tastic hit – and the result is simply pure delight.

The best thing of all, however, is seeing Corden and Carey reunited – particularly as ‘Mimi’ was the first ever celebrity to agree to appear on Carpool Karaoke.

Speaking on Howard Stern's SiriusXM radio show, Corden revealed: “If you imagine an artist – just think of any artist in the world – they said no to it. I’m talking, like, who are the dudes who did Cotton Eye Joe? We were in those sorts of territories and they were like, ‘I’m not doing that.’”

Read more: Watch Adele on Carpool Karaoke

Thankfully, when he pitched the idea to Mimi, she “got it”, and history was made… although there were still a few bumps in the road (pun intended) to smooth out along the way.

“She came out and said, ‘Oh, I'm not singing today,’ and she went, ‘We'll just drive around and have a chat,’” recalled Corden.

“I went, ‘Oh, right. It's just, we call it Carpool Karaoke, so without that...’And then I thought, I've just gotta go. I've just gotta jump into it. Even if this bit is just me singing to Mariah Carey, it's still on the show. It may not be the recurring bit that we hope it is, but it's still probably on the show.”

Thankfully Carey was won over by Corden’s enthusiasm, and joined in to sing Always Be My Baby, Vision of Love, Thirsty, and Ol’ Dirty Bastard’s Fantasy.

“To her credit, she got involved and it was wonderful,” said Corden.