Actress Keeley Hawes is set to star in the new series of Doctor Who as one of the Doctor's new foes.
The star will take on the role of an evil banker named Ms Delphox, who also has a dark secret.
Show-runner Steven Moffat said: "Anyone watching the amazing Line Of Duty will know that Keeley Hawes is having one hell of year.
"And now it's about to get even better as she achieves the greatest villainy yet attempted on Doctor Who: she plays a banker."
Fans of the actress who watched Hawes in the original series of Spooks, as well as the brilliant Ashes to Ashes will no doubt be excited to see her take on the Time Lord and his companion Clara Oswald, played by Jenna Coleman.
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 new episode is directed by Douglas Mackinnon, whose previous work includes Line of Duty and Doctor Who.
The story is penned by Sherlock writer Steve Thompson, and sees the twelfth Doctor and his companion, meet Ms Delphox when they arrive "on a strange and puzzling planet".
The new series will also star Peter Capaldi as the Doctor, taking over from Matt Smith, who played the eleventh incarnation of the Gallifreyan.
The episode is set to air in the autumn.
(Words: Elinor Block)