SCOTTISH screen star Kelly Macdonald will appear in the next series of TV police drama Line of Duty as the “most enigmatic adversary AC-12 have ever faced”.

The Trainspotting and Boardwalk Empire actress will play Detective Chief Inspector Joanne Davidson, the senior investigating officer in an unsolved murder, whose unconventional conduct raises suspicions at the anti-corruption unit.

The National: (Left to right) Vicky McClure, Adrian Dunbar and Martin Compston in Line of Duty(Left to right) Vicky McClure, Adrian Dunbar and Martin Compston in Line of Duty

Macdonald will join fellow Scot Martin Compston, Vicky McClure and Adrian Dunbar when filming on the sixth season of the BBC One drama starts next year.

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The 43-year-old is best known for roles in the Trainspotting films, lavish TV drama Boardwalk Empire and films Gosford Park, No Country For Old Men and Intermission.

Line Of Duty writer and showrunner Jed Mercurio 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.”