The 38-year-old actress will guest star in an episode of Peter Capaldi's first series as the Time Lord, playing a mysterious banker named Ms Delphox who is described as "a powerful, out-of-this-world character with a dark secret".
Keeley, who is currently starring in Line of Duty, is said to have already started filming alongside Peter.
Keeley Hawes will play the latest Doctor Who villian
A show source told the Mirror, "Her episode will be somewhere in the middle of the next run of episodes. Keeley was very excited to be involved, but she is hot property at the moment so we are delighted to get her.
Doctor Who boss Steven Moffat added, "Anyone watching Jed Mercurio's amazing Line of Duty will know that Keeley Hawes is having one hell of a 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."
Keeley will be joining Peter Capaldi and Jenna Coleman on the Doctor Who set
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".
Keeley said of her appearance, "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."