Stephen Graham doubted his comedy acting while shooting 'Code 404'.
The 46-year-old actor asked his co-star Daniel Mays for advice during the first few days of filming the Sky One series, because he was "nervous" about being funny in the programme.
Speaking to BANG Showbiz and other media during a 'Code 404' Q&A, he said: "At first, I was quite nervous, actually. I said to Danny, 'I can't do this mate, I don't really know what to do here'. And he was great with me because he's such a generous actor anyway and a lovely fella.
"He was like, just do what you do, play it normally ... just find the truth in it. I was like, 'OK'. And then that's when I kind of found my place in it."
The 'Line of Duty' actors appear as a top crime-fighting duo, Daniel as DI John Major and Stephen as DI Roy Carver, in the Special Investigation Unit at the Met.
When John is suddenly gunned down and killed, his body his sent to an experimental Artificial Intelligence project to bring him back from the dead.
John 2.0 looks and sounds like the original but his deteriorating crime-fighting skills leave Roy grappling on the frontline - and the character had Stephen in stitches.
Stephen said: "I'm the straight man. So Dan's off doing all these wacky things and his face ... some of the faces he pulls had me in stitches.
"He's great, his comic timing is brilliant. So I just try and play that kind of fella who's a little bit p***ed off and a bit miserable."
Daniel's "wacky" acting had Stephen struggling to hold it together between takes and the 'Snatch' star had to chew his lip to stop himself from ruining the shot.
He explained: "It was probably the most fun I've ever had on a set and I've been lucky, I've done some really good stuff and some great things. But I've never laughed so much.
"About three weeks into it I realised I had all these little things on the inside of my lip. And I realised, when the camera's on [Daniel], I'm biting my lip ... I had proper little dents on the inside of my lip. The amount of times we corpsed and the fun we had, it was just a joy."
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