Anna Maxwell Martin will return to Line of Duty as DCS Carmichael in this Sunday's episode, it has been revealed.
Fierce interrogator Carmichael appeared towards the end of series five of the drama, arriving at AC-12 from AC-3 to investigate possible corruption involving Ted Hastings (Adrian Dunbar).
In the most recent episode it was revealed that due to budget cutbacks, three branches of the anti-corruption unit - including AC-3 and AC-12 - will be merged, with Hastings being forced into an early retirement.
Carmichael's return suggests that she could be in line to head up the new merged entity and take control of Hastings's current investigation into Acting Superintendent Joanne Davidson (Kelly Macdonald).
Speaking about her return, Maxwell 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."
Line of Duty continues Sunday at 9pm on BBC One.