Eddie Redmayne has revealed he was so nervous about appearing at Comic Con for the first time that his co-star Colin Farrell had to calm him down with a back rub.
The actor plays Newt Scamander in the latest Harry Potter film Fantastic Beasts And Where To Find Them, which is released in cinemas next month.
Appearing on the Graham Norton Show, Redmayne said he felt like a "wannabe Justin Bieber" after appearing in front of thousands of people at the comic festival in July.
He added: "I'd heard from friends what the experience was, but I had no idea how big it would be.
"I was chronically nervous to the extent that I had Colin Farrell giving me a back rub and whispering sweet nothings into my ear trying to calm me down."
Asked if he is ready for worldwide recognition after entering the world of Harry Potter, Eddie said: "People say, 'Are you prepped for it?' But I'm not sure what that means.
"I had a weird moment on the Tube today. I was sitting there and suddenly a flash goes off from the person opposite me. I looked up, they looked at me and I looked at them and then there was a really awkward 47 seconds as I waited for the next stop and dashed off."
He added that he "spent seven months in the gym" to prepare for a scene when Scamander removes his shirt, only for the scene to be cut.
Eddie appeared on the BBC One show alongside Benedict Cumberbatch.
The pair compared their experiences playing British scientist Stephen Hawking, with Benedict recalling getting drunk with the world-renowned theoretical physicist.
"It is the most extraordinary experience. We were at the Royal Society for a discussion on the future of science and it was a long night so we decided to go for a drink.
We got knee deep in Margaritas and it was at that drunken moment I thought I would tell him I was playing Khan in Star Trek. Stephen was the only person I told. He liked the fact I had told him. It made him smile."
He also revealed he had performed the marriage ceremony for his friend and Strictly Come Dancing star Judge Rinder.
Benedict said his friend's performances on the BBC dancing show had been "extraordinary".
"I had no idea he could dance like that. To see a dear friend do something so unexpectedly brilliant like that fills me with pride," he said, adding: "When it gets crucial, I'll vote for him."
Breaking Bad actor Bryan Cranston and American singer LeAnn Rimes also appeared on the sofa with Norton.
The Graham Norton Show airs on Friday on BBC One at 10.35pm.