Graham Norton has revealed which guest was ‘hell’ to interview on his show.

Norton has been chatting to celebrities for almost 20 years on The Graham Norton Show and has invited all kinds of A-listers onto the famous red sofa, including the likes of Emma Stone and Will Smith.

More recently, he’s welcomed Taylor Swift, who spoke about her engagement to fiancé Travis Kelce, as well as Emily Blunt, Cillian Murphy and Julia Roberts.

Norton recently opened up about what it’s been like, revealing which guest in particular was ‘hell’ to interview.

Speaking at the Henley Literary Festival, according to The Independent, Norton explained: “If you ever see a drunk person on the show, it’s because they’ve arrived drunk – we have not made that happen.”

He then went on to provide details on one guest, who came on the show back in 2013.

Norton explained that while at first, the guest didn’t seem drunk at all, it was 15 minutes into the show when he started acting differently.

Norton has spoken about one guest in particular (BBC)

Norton has spoken about one guest in particular (BBC)

Norton explained: “Mark Wahlberg was a weird one because when he arrived, he didn’t seem drunk.

“He told me about his film, told me a couple of stories about stunts going wrong or whatever, and then it was only 15 minutes into the show when whatever the hell was in his system really took hold – and it was hell.”

Wahlberg appeared on the show while promoting his movie Broken City alongside other guests Sarah Silverman and Michael Fassbender.

At one point, Wahlberg even sat on Norton’s knee and began caressing his face.

Wahlberg could be seen sitting on Norton's knee (BBC)

Wahlberg could be seen sitting on Norton’s knee (BBC)

“No one could tell a story,” Norton explained.

“You tried to tell a story, he’d just interrupt and, at one stage, Michael Fassbender was telling a story and this one was going quite well. He was really getting into the heart of the anecdote.

“I thought, ‘this one is going well – I wonder why’ and I looked over at Mark Wahlberg and he was asleep. So yeah, we don’t encourage that.”

Norton also explained just how much alcohol guests are given before they come on the show, explaining that it’s a myth that producers encourage drinking.

“There’ll be a drink waiting for you if you want one and then, while we’re showing a clip or getting the music ready, they might be able to rush in and top you up, but the most you can have is two, three tops,” he said.

“So if anyone does want to appear on the show and be drunk, my tip to you would be pre-load.”

Wahlberg said people took it 'too seriously' (BBC)

Wahlberg said people took it ‘too seriously’ (BBC)

Wahlberg later spoke out about his appearance on the show, explaining to Digital Spy that some took it ‘too seriously’.

He said: “I tried to do a bit, and some people took it a little too seriously.”

Tyla has contacted Wahlberg’s reps for comment.