Robert Glenister and Goran Visnjic are the latest stars to join the cast of Doctor Who.
Glenister is to make a return to the BBC sci-fi series after appearing in the show more than three decades ago.
The Spooks actor, 59, first appeared in the BBC series in 1984 when he was 24.
The episode, called The Caves Of Androzani, told the tale of a space war being fought by a businessman and an android builder over a life-prolonging substance called spectrox.
Glenister will return for the forthcoming 12th series in a new role.
He said: “I first appeared in Doctor Who in The Caves Of Androzani at the tender age of 24 in 1984.
“Thirty-five years later I got to be in it again at the not so tender age of nearly 60. How time flies!”
Croatian-American actor Goran Visnjic will also guest star in the series, playing one of his “favourite people in history”.
Visnjic, 47, is best known as Luka Kovac in the medical TV drama ER.
He said: “I’ve always been a huge fan of Doctor Who, so when the offer to play one of my favourite people in history came, it made me so happy to be part of the show and it turned into this awesome dream job.”
Executive producer Matt Strevens said: “One of the great joys of Doctor Who are the legendary actors who want to come and join in the Doctor’s adventures.
“We were thrilled to welcome Goran and Robert, whose work we’ve loved and admired for years.
“They create two iconic characters who are going to delight and entertain.”
On Thursday it was announced that Stephen Fry and Lenny Henry are also set to join Jodie Whittaker in guest roles.
Doctor Who will return with a new series in early 2020.
With reporting by Press Association.
