Line of Duty is known for its super tense scenes.
But show favourite Vicky McClure, who plays sharp-talking DI Kate Fleming on the hit BBC show, has revealed it can be just as tense when the cameras aren’t rolling.
She said there were regular bust-ups between co-stars, telling The Mirror: “The reality of it is of course we have, of course we have p***** each other off. It would be wrong of me to say ‘that has never happened’ as that would be a lie.
“But in the same way it is with family, it’s never something so bad it’s not repairable. I might not have had any sleep that night.
“He [Martin Compston, who plays DS Steve Arnott] might not have had any sleep or loads of lines to learn, you get up to set you are knackered, there’s a lot going on.”
The sixth series started on Sunday night, delighting fans who had waited eagerly for its return.
The episode was watched by the biggest number of people yet, with 9.6million viewers tuning in.
Fans were all left asking the same question after the first episode which was full of explosive twists and turns.
But it was one acronym that really got viewers talking – and scratching their heads.
Throughout the show CHIS kept popping up – sending everyone rushing on to google.
CHIS stands for Covert Human Intelligence Sources.
Line of Duty continues on Sunday at 9pm on BBC One. You can catch up on the show on BBC iPlayer.