The actor, who plays Superintendent Ted Hastings, was interviewed by Susanna Reid and Adil Ray the morning after viewers witnessed one of the show’s most dramatic endings to date.
Dunbar hinted that details surrounding the show’s biggest mysteries, including the identity of the fourth and final corrupt member of the crime syndicate H, are actually out there to be discovered.
*Potential spoilers follow – you have been warned*
He added that “hardcore fans” of the show already know the fate of DI Kate Fleming, who was involved in the fifth episode’s cliffhanger.
Whether or not he was referring to the old trailer being recirculated by fans in the wake of last night’s episode is unclear. Since its broadcast, sleuths have highlighted the fact the clip contains footage that is yet to be aired.
While Dunbar teased that “Line of Duty fans know what’s going on”, he also cryptically stated: “Yes, there’s been a very big clue – there is a clue out there as to what happens next.”
He added that the BBC “sends him notes” telling him what he is and isn’t allowed to talk about during interviews.
“Now and again, leaks do happen,” he said, continuing: “It’s a show that depends on collusion with the public.”
One fan praised Dunbar for being unafraid to “drop some big hints”, with many wondering what clue he could be referring to.
Line of Duty continues next Sunday (25 April) at 9pm on BBC One.
Find our rundown of the episode’s big events here.