The BBC announced Graham’s casting in a cryptic e-mail with the subject line, “CCTV image of a suspect AC-12 wish to talk to as part of an ongoing investigation”, accompanied by a picture of the actor pulling off a black balaclava.
He’ll be joining series regulars Adrian Dunbar, Martin Compston and Vicky McClure as the series continues filming in Northern Ireland, ahead of an expected broadcast in 2019.
Stephen Graham joins the cast of Line of Duty series five (BBC)
The picture – and the description – will immediately have fans questioning whether Graham has some connection to the mysterious “balaclava man” conspiracy revealed at the end of series four, when lawyer Jimmy Lakewell revealed that there was a group of disguised figures blackmailing and attacking people while maintaining links with corrupt police officers on the force.
Of course, this could be a red herring and it could be that Graham will be joining AC-12’s investigation in a more professional capacity – or that he’ll be the guest actor playing the police officer AC-12 are looking into this year.
Given creator Jed Mercurio’s habit of killing off major stars, Graham’s character could also be dead within the opening episode…
Still, whatever the case, we’re dusting off all our old balaclava man theories ahead of the drama’s return next year.