Stephen Graham "had to pinch himself" working with Cillian Murphy on 'Peaky Blinders'.
The 47-year-old star - who has appeared in the likes of 'This Is England', 'Gangs of New York' and 'Line of Duty' - has filmed scenes for the upcoming sixth series of the BBC One period drama, and he was star-struck by the Tommy Shelby actor.
Speaking on Radio X's 'The Chris Moyles Show', he said: "Cillian’s such a wonderful actor, he’s amazing and what a lovely, lovely, lovely fella.
"To the extent, Chris, where there was a couple of moments – I had to pinch myself a couple of times because I was sat there in a scene with him, doing a rehearsal and stuff and I’ve kinda gone, ‘Ahh that’s Tommy Shelby!’ "
Stephen praised his co-star as "an absolutely lovely fella and a phenomenal actor", and admitted he took a moment to take everything in before getting to work.
He added: “Well what I managed to do was I managed to do that before they said action.
“I had a proper look round and then it was like, ‘Alright lad, best put your footy boots on here and your shin pads, let’s get ready, here we go, on the pitch!’.
"But at first [inhales], ‘Ok, oh wow!’ ”
Stephen revealed the news he was joining 'Peaky Blinders' back in April as the show's social media team gave fans a first look at him in his role.
Alongside the snap, they wrote: "We're thrilled that @StephenGraham73 has joined the cast of #PeakyBlinders series 6. (sic)"
The incoming star kept his response short and sweet, as he revealed he is grateful for the experience.
He replied: "Thanks for having me".
Plans for Stephen to join the cast have been in the pipeline for a long time, as the show boss confirmed back in July 2019 he wanted to get him on board.
However, in April last year the actor said: "I was supposed to be starting 'Peaky Blinders', but that has been put on hold indefinitely.
"My agent had spent a load of time putting that together."