Line of Duty actor Nigel Boyle secretly hinted that Ian Buckells was H four years ago after suggesting that there was "more to him than meets the eye".
Viewers were left utterly stunned - and more than a little disappointed - after the bumbling cop was exposed as the 'fourth man'.
While fans were raising their eyebrows at the revelation, Nigel had teased that they should watch out for his character during an interview in 2017.
He told Digital Spy as he was promoting series four: "There's definitely more to Buckells than meets the eye!
"He's very competent, very good at what he does, he's the go-to guy, but he's certainly not a popular guy – he's petulant, and a bit of a jobsworth I think.
"I don't think people give him enough credit, just because of his personality!"
The finale saw Ian Buckles brought in for questioning after the AC-12 team found out he was the one behind the laptop with his misspelling of "definately".
After repeating "no comment" to Ted Hastings' questions, he finally responded after he was branded a "blundering fool".
"Yeah, right. I'm a blundering fool," he said with a smirk. "I'm the only one that's made mugs out of you lot."
And fans were largely unimpressed and took to Twitter to comment.
One tweeted: "We waited 10 years for Ian Buckells to be revealed as the OCG mastermind #LineofDutyFinale #LineOfDuty."
While another commented: "Waited a week for that - H being Ian Buckells! #LineOfDuty #LineofDutyFinale."
A third wrote: "NO WAY IS BUCKELLS THE TOP LYNCHPIN OF ALL THIS #LineOfDuty."
"The only good thing about that #LineofDuty finale is ... now we know there’s DEFINITELY a series 7 because if Buckells is H I’m f**kin Beyoncé!" another insisted.
*Line of Duty is available to watch BBC iPlayer
