Indira Varma will star in Doctor Who as the mysterious Duchess who “unleashes her terror”, the BBC has announced.

The 49-year-old Olivier Award-winning actress, known for playing Ellaria Sand in Game Of Thrones, has previously played Suzie Costello in one of the science fiction show’s spin-off series, Torchwood.

The broadcaster previously teased a future episode with the tagline “dress to impress and beware the duchess” alongside images of actors in 1800s period fashion.

Mindhunter actor Jonathan Groff, Ncuti Gatwa, who is set to take over as the Time Lord, and Millie Gibson, who is playing the Doctor’s companion Ruby Sunday, were dressed in regency era-style clothing in the photos.

Varma said: “I’m thrilled to be in Doctor Who and particularly excited to be crossing cosmic paths with Ncuti, as the Doctor, and look forward to creating interplanetary mischief with him.

“I loved playing Suzie Costello for Russell T Davies in Torchwood so am thrilled to be entering this world again.”

Varma has also starred opposite Idris Elba in Luther, acts alongside Tom Cruise in Mission: Impossible – Dead Reckoning Part One, and featured in historical fiction series Rome and in Obi-Wan Kenobi alongside Ewan McGregor.

She is also a theatre actress, who won an Olivier Award for her portrayal of Liz Essendine in Noel Coward play Present Laughter and has been in productions of George Bernard Shaw’s Man And Superman and Anton Chekhov’s The Seagull.

Russell T Davies, who has returned as showrunner, said: “I’m overjoyed to be reunited with Indira after our Torchwood days, and this part is truly spectacular.

“A whole new audience will be hiding behind the settee when the Duchess unleashes her terror.”

BAFTA Scotland awards
Ncuti Gatwa (Jane Barlow/PA)

Other previously announced cast members include drag queen Jinkx Monsoon in an undisclosed role as the Doctor’s “most powerful enemy yet” and Heartstopper actress Yasmin Finney playing Rose.

To coincide with the show’s 60th anniversary, Doctor Who will return for three special episodes featuring David Tennant as the 14th doctor.

Sex Education star Gatwa, 30, will then take over as the 15th doctor with his first episode airing over the festive period.

He will be joined by Coronation Street actress Gibson, 18, who will become the youngest companion in the show’s history.

Doctor Who will air on the BBC in the UK and Ireland and streaming platform Disney+ will show episodes to audiences elsewhere.