Anna Maxwell Martin will return to Line Of Duty on Sunday, the BBC has announced.
The actress will reprise her role as Detective Chief Superintendent Patricia Carmichael.
The character appeared in series five of the acclaimed police drama, when she was brought in as an independent investigator amid doubts over the integrity of Adrian Dunbar's Ted Hastings.
Her return comes as Ted is facing a forced retirement.
Who is Anna Maxwell Martin?
Martin said: "Pat's back, I can't remember what she's doing there, nor would I be allowed to blab, but suffice to say she's got some new clobber and she's ready to bust some balls."
Martin, 43, is a two-time Bafta TV Award winner.
Her previous roles include the BBC's 2005 adaptation of Bleak House and the 2015 Agatha Christie adaptation And Then There Were None.
When is Line of Duty on TV?
Line Of Duty returned for its sixth series last month.
Its first episode was the most watched episode of a drama since 2018.
Line Of Duty airs on Sunday nights at 9pm on BBC One and BBC iPlayer.