Michael Buble believes Hannah Waddingham is the "spirit of Christmas"

He said: "What people wouldn't know was that 15, 16 years ago, I went to the West End to see her in Spamalot in London and I came backstage to meet her. And her and I became very good, just instant friends.

"She was wonderful and funny and humble and all these things. And she fought, just like I did, she fought a long time for her moment and it came with 'Ted Lasso'. And when [producer] Lorne [Michaels] and I first started talking about who I wanted to be on this show, I said to him, 'Listen, I need Hannah.'

"I said, 'Listen, she embodies what this holiday is about. She is the spirit of Christmas.' When you give beautiful things out to the world and to the universe, they do come back to you and she is proof that goodness and kindness and light will always come back," he continued. "And it was just honestly a joy."

Michael joked shooting the special has lead to the creation of a new "Brat Pack" featuring himself, Jimmy Fallon and Kermit the Frog.

Discussing the show - on which he will be backed by a 48-piece orchestra - he told 'Entertainment Tonight': "There's a real sense of elevation when Lorne Michaels called and said he wanted to produce, and that had a massive change.

"Coming in and doing it in the 'SNL' studios and having the writers and some of the cast…He's done this for so long, he has just such a great sense of style and it was just so beautiful.

"And the guests, of course having Jimmy Fallon come, who is a beautiful human being. My hero, Kermit the Frog, who is the sweetest man/frog ever.

"I believe Jimmy, Kermit and I may be the new Brat Pack. I don't know. You might see us out on the town, maybe a road movie.

"Camilla Cabello, I was just, eyes droopy, as my friend Sal was watching her sing her song. She's such a beauty, another great kid."