The Doctor Who Christmas special will see a major character make surprise return.
Captain Jack Harkness will return to Doctor Who in earnest for the first time in a decade this festive season.
Revolution Of The Daleks, set to air on Christmas Day, will see John Barrowman reprise the role of the fearless alien hunter as he aids Yaz, Ryan and Graham in their battle against the show's most famous villains.
Meanwhile, Jodie Whittaker's Doctor remains unable to help them in their fight, trapped inside a high-security space prison far from Earth and her Tardis.
Aside from a very brief appearance during the episode Fugitive Of The Judoon in January this year, Captain Jack was last seen on Doctor Who in the 2010 episode The End Of Time.
Barrowman said: "Putting on Jack's coat and setting foot back on the set of Doctor Who was just like going back home. It’s always thrilling to play Captain Jack.
"He's a character very close to my heart who changed my life, and to know the fans love him as much as I do makes his return even sweeter.
"I hope everyone enjoys Jack's heroic adventure with Thirteen."
Executive producer Chris Chibnall said: "A Doctor Who festive special means treats galore, and there's no bigger treat than the return of John Barrowman to Doctor Who for an epic and emotional feature-length episode.
"If anyone can blast away the sheer rubbishness of 2020, it’s Captain Jack. Daleks beware."
Matt Strevens, executive producer for BBC Studios, added: "After a tantalisingly brief appearance in Fugitive Of The Judoon, it’s a total joy and thrill to welcome back John as Captain Jack.
"One of the most iconic characters in Doctor Who lore, his presence ignites this festive special from the start."
Revolution Of The Daleks will air during the upcoming festive period on BBC One.
