Line of Duty's return is almost upon us. It's been nearly a year since Matthew "Dot" Cottan's dramatic exit and AC-12 have moved on, with a new case to investigate in search of police corruption. 

Welcomed into the fold this series is Thandie Newton, playing DCI Roz Huntley – the lead investigator in a huge case codenamed Operation Trapdoor. She has a suspect in her sights – but is he the right one? Or will AC-12 find dirt if they keep digging? 

Meet the cast below... 

DCI Roz Huntley (played by Thandie Newton)

Roz is a badass copper – the lead investigator on a huge case, she's trusted by her superiors to get a conviction and she executes her work with precision and skill. Respected by those she works with, Roz juggles a family with the demands of her job and the pressure from above – but is she nailing the right guy? Does she care more about putting a man in court than conducting a fair investigation?

Where have I seen Thandie Newton before?

British actress Thandie has made a name for herself in America, appearing in films Mission: Impossible II, Beloved, The Pursuit of Happyness and Crash (for which she won a Best Supporting Actress BAFTA). On TV, she played Kem – the love interest of Noah Wyle's John Carter – in ER and has recently been seen in HBO's hit sci-fi Westworld. She is currently filming the upcoming Han Solo spin-off in the Star Wars franchise. 

Forensic Investigator Tim Ifield (played by Jason Watkins)

Forensics expert Tim comes into conflict with Roz when he raises concerns he has with her investigation. Does the evidence he's seen match the case the police are putting together? Or does Tim have cause for concern?

Where have I seen Jason Watkins before?

Jason Watkins is a veteran of British television, acting since the late 1980s and appearing in the likes of Being Human, Conviction, Trollied, Doctor Who and W1A. He won a BAFTA for Best Actor in 2015 for his lead role in The Lost Honour of Christopher Jefferies and on film has cropped up in the Nativity series, Confetti and Bridget Jones: The Edge of Reason.