The 'Line of Duty' cast have started filming the sixth series.

Line of Duty

Line of Duty

The hugely popular BBC One thriller - which was created by 'Bodyguard' writer Jed Mercurio - will return later this year, and now the broadcaster has confirmed the team have started working on the upcoming run.

In a behind the scenes snap, Adrian Dunbar and Martin Compston can be seen on set as Superintendent Ted Hastings and Detective Sergeant Steve Arnott respectively.

They will be joined once again by fellow series lead Vicky McClure, who returns in the role of Detective Inspector Kate Fleming.

The new season - which is set 18 months on from the fifth series - will centre on a new case for AC-12, with Kelly Macdonald joining the cast as new, enigmatic Detective Chief Inspector Joanne Davidson.

Also confirmed for the upcoming run are Shalom Brune-Franklin, Perry Fitzpatrick, Andi Osho, and Prasanna Puwanarajah.

Mercurio returns as writer for the sixth series, and Gareth Bryn, Daniel Nattheim and Jennie Darnell will direct, and Ken Horn will be back as producer.

The showrunner previously promised that Kelly's alter ego will be an "enigmatic adversary" for Vicky, Martin and Adrian's characters in the BBC One show.

Jed said: "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."

Piers Wenger, Controller of BBC Drama, added: "We're delighted that Kelly Macdonald is coming on board for series six. She's one of the UK's most versatile actors and we're excited for viewers to see what Jed's scripts have in store for her when she joins the Line of Duty team."