As Stephen Graham joins as guest lead alongside Rochenda Sandall.
Together they'll play two pivotal figures in a deadly organised crime group. John Corbett and Lisa McQueen are known to have links with corrupt police officers and suspected to be under direct command of the shadowy figure known only as 'H'.
They become persons of interest to AC-12 following an explosive chain of events. The new series will follow a new case for AC-12, set nearly two years on from the hit crime drama's previous instalment.
On joining Line of Duty, Stephen Graham said "It's an honour to have been asked to be part of the Line of Duty team. I’m especially looking forward to working with Martin Compston and Vicky McClure again."
Whilst Rochenda Sandall added "I am honoured to be working with such a talented team of people, and to be working side-by-side with Stephen Graham, who I have watched and admired onscreen since I was young."
With filming on Line of Duty series five now underway in Belfast, the BBC have revealed the cast for the new six-part series. Series regulars Vicky McClure, Martin Compston and Adrian Dunbar all return as DS Kate Fleming, DS Steve Arnott and Supt. Ted Hastings.
Vicky McClure said "Thanks to such a fantastic response from the Line of Duty audience, it feels extra special to be back filming series 5. I absolutely love working with Martin and Adrian, and Jed has without a doubt stepped it all up a gear this series. His writing just gets better and better. We have lots of great new cast members and I’m over the moon Stephen is on board, he’s a good friend and one of the finest actors. I’m already excited for the twists and turns to hit the screens. "
Martin Compston added "I’m absolutely delighted to be back with the AC-12 family, brought together once again by the phenomenal scripts of Jed Mercurio. A huge part of the show’s success over the years is the incredible guest stars we’ve had and this year is no different. It’s an absolute joy to be working with Stephen Graham again - someone I’ve always looked up to as an actor. He’s a brilliant addition to the Line of Duty team. It’s gonna be explosive!”
Whilst Adrian Dunbar said “Every time we open the scripts and every time Jed does it again. It’s great to be back with my Belfast family, even if the children appear to be a little wayward…"
Also returning are Maya Sondhi, Polly Walker, Aiysha Hart, Tony Pitts and Andrea Irvine all return as PC Maneet Bindra, Gill Biggeloe, DS Sam Railston, Det. Ch. Supt. Les Hargreaves and Roisin Hastings.
Taj Atwal (In The Club) and Richard Pepple join the cast as new series regulars PC Tatleen Sohota and PS Kyle Ferringham. And other newcomers include Susan Vidler (Shetland), Sian Reese-Williams (Hidden), Ace Bhatti (No Offence) and Elizabeth Rider (Informer).
Following the success of Bodyguard, showrunner Jed Mercurio said "After the hysteria surrounding Bodyguard, it's a relief to be back in the day job. I'm delighted to be working with the old gang and welcoming our brilliant newcomers led by Stephen Graham and Rochenda Sandall."
Line of Duty returns in 2019 on BBC One