Stephen Graham argued with Jed Mercurio over the death of his Line of Duty character.
Stephen's gang leader John Corbett - who was actually an undercover cop - met a grisly end when his throat was slit in season five and Stephen has revealed that he tried to fight with writer and creator Jed about the scene but Jed ultimately won.
I actually said to him: 'How many people's throats have you slit?'
Speaking on The Graham Norton Show's New Year's Eve special, he explained: "It was kind of a shock, wasn't it?
"The weird thing about it is when you work on a death scene you want to do it as real as possible, but Jed used to be a doctor so when I was being dramatic in rehearsal he would say things like, 'You wouldn't do it like that, you wouldn't choke on your own blood'.
"I actually said to him: 'How many people's throats have you slit?'"
Read more: Jed Mercurio shares 'clue' for series six
And that wasn't the only drama on set for Stephen as he previously admitted he was almost mistaken for a real criminal while shooting scenes for the police corruption drama.
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."
And Stephen, 46, also spoke to an Army Intelligence officer to help with his Line of Duty role.
He said: "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 highest order."
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