Keeley Hawes is to take on a villainous role in Doctor Who - as a banker.
The actress will guest star in an episode in Peter Capaldi's first series as the Time Lord.
"Anyone watching the amazing Line Of Duty will know that Keeley Hawes is having one hell of year," said Doctor Who boss Steven Moffat.
"And now it's about to get even better as she achieves the greatest villainy yet attempted on Doctor Who: she plays a banker."
Hawes, who previously starred in BBC dramas Ashes to Ashes and Spooks, plays Ms Delphox, who is described as "a powerful out of this world character with a dark secret".
The story, written by Steve Thompson, sees the twelfth Doctor and his companion, Clara Oswald (Jenna Coleman), meet Ms Delphox when they arrive "on a strange and puzzling planet".
The episode is directed by Douglas Mackinnon, whose recent credits include Line of Duty. He has directed four other Doctor Who stories including The Sontaran Stratagem (2008) and Cold War (2013).
Hawes said: "I am delighted to join Doctor Who and to be working with this incredible team. Ms Delphox is a great character and someone I've had a lot of fun playing."
The story will be screened in the autumn.