Line of Duty star Martin Compston says 10 years of work on the hit BBC cop drama has been leading to tonight's dramatic finale in which viewers will discover the identity of the notorious bent copper 'H'.
The Scottish actor plays Detective Inspector Steve Arnott in the show alongside Enniskillen actor Adrian Dunbar, who stars as Superintendent Ted Hastings.
The officers work in the fictional AC-12 anti-corruption unit, which has been hunting corrupt cop 'H' for several seasons of the show, filmed largely in Northern Ireland.
The drama has proved to be hugely popular, with the penultimate episode of season six watched by 11 million people last weekend.
As millions of fans across the UK wait on tenterhooks for tonight's finale and the unmasking of 'H', Martin Compston said the team had been working towards this point from the start.
Speaking on the BBC's The Afternoon Show podcast he said: "That's the one thing I can say. I won't go the Jo Davidson 'no comment' route, but our tagline is that every investigation has led to this point and it has.
"All 10 years, all six series, has been kind of building to tonight. There are big pay-offs coming and it feels like a natural end to this story arc that's been keeping us going for so long."
When asked about whether this was the end of Line Of Duty, he said the cast and crew did not know but would not return unless they felt another season had "legs".
He added: "The genuine answer is we don't know, but that's nothing different.
"Every series, Jed takes a couple of months off after it and there's stuff that's way above my paygrade in terms of the data and analytics that comes in.
"There's all this stuff now with 28-day figures because you've got streaming and so on. He likes to sit down in the cold light of day, take the emotion out of it and look at it then.
"I will say for sure that we won't come back just for the sake of it. We'll only come back if he believes there's a story to be told and there's more legs in it.
"There's also a question now of legacy. You know, if it does wrap up, great, do you want to go out with a bang?
"But all that stuff will come into play and I'd say in a couple of months time we'll take a decision."
Speculation has been rife for months about the identity of the notorious 'H', who is in fact not one person but four.
The codename refers to a group of high-ranking officers within the fictional Central Police.
Three have already been revealed - Detective Inspector Matthew 'Dot' Cottan, Assistant Chief Constable Derek Hilton and Senior Legal Counsel Gill Biggeloe - with the fourth remaining a mystery until tonight.
Viewers were first introduced to 'H' in the finale of series three, when DI Cottan recorded a dying declaration and tapped out a clue as to the identity of the corrupt officer.
However, when inspecting footage of the declaration in series five, Detective Inspector Kate Fleming, played by Vicky McClure, and DI Arnott realised Dot was tapping his fingers four times, leading them to the conclusion that there were four rotten apples in the force.
AC-12 carried on with their search for bent coppers, and ACC Derek Hilton was unveiled as corrupt before he was killed off .
Lawyer Gill Biggeloe, who worked for Central Police, was also revealed to have links to the shadowy Organised Crime Gang (OCG), but AC-12 still believes there is a fourth man, or woman, out there pulling the strings.
Tonight all will be revealed, including the identity of the final 'H', during the seventh and final episode of season six of Line Of Duty on BBC One at 9pm.