Domhnall Gleeson was mortified to learn he'd have to dance in Taylor Swift's Opalite video.

The Paper actor was among a string of guests from The Graham Norton Show who the pop superstar invited to be in the promo with her - along with Cillian Murphy, Greta Lee, Jodie Turner-Smith, Lewis Capaldi and the host himself - and while he was thrilled to be a part of it, he doesn't think he'd have pulled off his storyline without Taylor's "trust".

He told The Guardian newspaper: "They told me the day before there was going to be a dance. I was like, are you f****** joking? I'm terrible at it!"

Domhnall admitted he spent the whole night practising in front of the mirror but Taylor ultimately got him through.

He added: "She said 'full send', though I didn't know what that phrase meant. She was like, 'The moves don't matter. You just gotta go for it and love it, and just trust in it and experience it.'

"The believing in it and the joy of it helps you do it."

The 43-year-old actor admitted it was a "wild" idea to reunite all the talk show guests for the video and he doesn't think anyone other than Taylor would have pulled it off.

He recalled: "Two weeks [after the show], we got an email. Like, wild!

"No one else in the world can come up with an idea like that and make it happen."

But the Incomer actor declined to confirm if he attended Taylor's wedding to Travis Kelce in July.

Asked directly, he said: "Er … Can I plead the fifth?"

Domhnall previously admitted starring in the Opalite video was one of the most surprising highlights of his career.

He joked to E! News: "I'm 42, I've got no business being in Taylor Swift's music video. It was incredibly exciting. I had done one with Hozier a couple of years before that that I was incredibly proud of. And then the other music video, I joined a great Irish band called Squarehead.

"I've been in a few of these music videos. I'm equally proud of all of them, but there was something special about doing a dance number with Taylor that was not on my bucket list. I didn't realise it was on my bucket list until it happened."

Domhnall and Taylor appear in matching blue-and-orange tracksuits for a full choreographed routine - a moment that quickly became a fan favourite.

The singer revealed that the entire idea was sparked by a joke Domhnall made during their joint appearance on The Graham Norton Show last October.

Taylor wrote on Instagram in February: "I remember thinking I got ridiculously lucky with the group I was paired with. All people whose work I've admired from afar. When we were all talking during the broadcast, Domhnall made a light-hearted joke about wanting to be in one of my music videos. He's Irish! He was joking!"

She added: "Except that in that moment during the interview, I was instantly struck with an idea.

"Like a school group project but for adults and it isn't mandatory. To my delight, everyone from the show made the effort to time-travel back to the 90's with us and help with this video."