Line of Duty fans were left stunned as they recognised DSI Ian Buckells from a classic TV show.
DSI Buckells has been part of the Line of Duty cast since the first season of the BBC drama.
He joined as a Detective Inspector.
Since, he has risen through the ranks, more recently becoming a Detective Superintendent.
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DSI Buckells has had a more prominent role in season six, heading up Gail Vella's murder investigation.
However, after a number of mistakes were made and further incidents occurred within the case , DSI Buckells was arrested on suspicion of perverting the course of justice.
Operation Lighthouse files were then found in the boot of his car.
Tonight, DSI Buckells was interviewed by Superintendent Ted Hastings and DI Steve Arnott.
But, fans on Twitter recognised him from elsewhere.
DSI Buckells is played by Nigel Boyle.
While he is best known for his role in Doctors, he also played a landlord in The Inbetweeners.
He famously refused to serve character Will McKenzie in the local pub.
Making the connection, fans were left stunned.
Jason tweeted: "Never trusted this Ian Buckells fella ever since he refused to serve Will in episode 1 of The Inbetweeners."
Benn said: "Not gonna lie, my mind was blown when I found out that the actor who plays Ian Buckles in #LineOfDuty is the same dude from the bar in the Inbetweeners."
And Ian wrote: "Just learned that DCI Buckells was the barman (“ID, please) in the first episode of The Inbetweeners. Mind well and truly blown."
