Stephen Graham has said he was almost mistaken for a real criminal during the filming of Line Of Duty.
The This Is England star joins the crime drama for its fifth series as the manhunt for corrupt senior police officer H resumes on BBC One on Sunday night.
Graham joins the cast as villain John Corbett, part of the organised criminal group being investigated by anti-corruption unit AC-12 in the upcoming episodes.
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 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.”
He added “As a kid we used to play army and would run round the garden. Now, roll on 45, I’ve got an M16 in my hand and been told: ‘here’s a load of ammunition, you’re not going to hurt anyone, just point it over there, don’t point it directly at each other, and shoot!’
“It’s a lot of fun jumping out of cars, shooting guns and rolling around on the grass and everything – it’s brilliant.”
Jed Mercurio, who has penned all five series of the show, as well as the ratings hit Bodyguard, said the show will “enter new territory” as it enters the world of organised crime.
He added: “The so-called ‘balaclava men’, the organised criminal group who’ve been featured on and off through the preceding four seasons, are now featured more prominently in this series.
“John Corbett is probably our most dangerous and villainous character that we’ve ever featured as an antagonist.
“He’s involved in serious criminal offences, he’s the leader of a ruthless gang of violent criminals and I would say that he presents probably the biggest ever challenge to AC-12.
“Rather than the aftermath (of criminal activity) being investigated by AC-12, we are actually with the criminals as they commit their offences.
“That means that there is high jeopardy and big action sequences, in fact probably more action sequences over the first few episodes of the series than were ever done before.”
The series will feature the return of Martin Compston, who plays DS Steve Arnott, Vicky McClure as DS Kate Fleming and Adrian Dunbar in the role of Superintendent Ted Hastings.
Line Of Duty returns to BBC One on Sunday at 9pm.