I have recently become almost worryingly obsessed with Line of Duty, the very excellent UK cop show of which Seasons 1-4 can be found on Netflix and Stan, Season 5 you have to buy on iTunes and Season 6 we’re all waiting for like rabid dogs.

But the good people at BBC (the show airs on BBC One in the UK) have finally dropped some details about the upcoming season of Line of Duty, which the show’s writer / showrunner Jed Mercurio has vaguely hinted will be airing in 2020.

Yesterday the official BBC site shared the news that Scottish actor Kelly Macdonald — who previously appeared in Trainspotting, No Country For Old Men and Boardwalk Empire — has been cast as the “guest lead” for the upcoming season, filling the spot of Line of Duty guest leads before her including Lennie James in Season 1, Keeley Hawes in Season 2 and 3, Thandie Newton in Season 4 and Stephen Graham in Season 5.

According to the BBC report, Macdonald will star as DCI Joanne Davidson, the senior investigating officer of an unsolved murder.

She piques the attention of our mates at AC-12, the anti-corruption unit tasked with sniffing out “bent coppers” that Line of Duty follows each season, after her “unconventional conduct raises suspicions”.

BBC confirms that our AC-12 faves Martin Compston (DS Steve Arnott), Vicky McClure (DI Kate Fleming) and Adrian Dunbar (Superintendent Ted Hastings) will return to Line of Duty, which begins filming in early 2020.

Showrunner Mercurio said in a statement:

We’re honoured that Kelly Macdonald will join Martin, Vicky and Adrian in series six of Line Of Duty. DCI Joanne Davidson will prove the most enigmatic adversary AC-12 have ever faced.

Fellas, find your nearest dark alley because this is gonna get messy.