Stephen Graham spoke to an Army Intelligence officer to help with his 'Line of Duty' role.
Stephen Graham
The 45-year-old actor has joined the hit series as gang leader John Corbett - who is actually an undercover cop - and after speaking to writer Jed Mercurio about his character, he decided to do some research into what it would take to play such an involved role.
He told ES Magazine: "Jed writes fully rounded characters, which is a gift. But we talked a lot about [Corbett's] backstory.
"I spoke to a friend of mine who did a lot of undercover work, not as a police officer but in Army Intelligence.
"He put his life on the line. Basically, what I came away with was that being undercover is acting of the f***ing highest order."
But Stephen insists there isn't really a comparison between being undercover for real and acting for TV and film.
He said: "We get in make-up, put on a costume and we entertain people. We try and dive into these characters and tell a story. What they're doing is putting their lives at risk. Imagine how high the stakes are."
Filming hasn't always been plain sailing for Stephen though, as he recently admitted he was almost mistaken for a real criminal while shooting scenes for the police corruption drama.
Last month, he said: "There was one bit when we'd just committed a robbery and we shot off, and we were actually driving through the streets of Belfast with our balaclavas and machine guns in the car and we realised we'd better get back to set.
"So that was quite funny, but wouldn't have been too funny if people had seen. It was all a lot of fun; it was a lovely environment to work in."
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