Matt Lucas will be making Christmas come early for Doctor Who viewers as he returns for the new series.
The comedian, who starred alongside Peter Capaldi and Alex Kingston in last year's Christmas Day special as Nardole, will appear from the opening episode of series 10, which starts filming in Cardiff from June 20.
His character was last seen sharing the body of King Hydroflax (Greg Davies) with River Song's former husband Ramone (Phillip Rhys) and working in a restaurant situated near the Singing Towers, where the Doctor - also married to River Song - spends his final night with her.
Matt, who will be joining new companion Pearl Mackie, said: "I'm chuffed to bits that Nardole is returning to the Tardis for some more adventures.
"I loved acting with Peter and I'm excited to work with Pearl."
Writer and executive producer Steven Moffat said: "Delighted and slightly amazed to be welcoming Matt Lucas back on to the Tardis - and this time it's not just for Christmas, he's sticking around.
"One of the greatest comedy talents on planet Earth is being unleashed on all of time and space."
It will be Pearl's first appearance as the Doctor's new assistant, as she takes over from Jenna Coleman.
The BBC hit is her first major television role after starring in The Curious Incident Of The Dog In The Night Time in the West End.
Jekyll and Hyde star Stephanie Hyam also has a guest role in the new series.
Steven, who will step down as showrunner at the end of the upcoming series, has penned the opening episode, while Olympic opening ceremony writer Frank Cottrell-Boyce has crafted the second episode.
Mike Bartlett, the writer behind multi-award winning Doctor Foster, and Sarah Dollard, who penned Jenna's death in Face The Raven, will also write episodes.
Doctor Who will return in December 2016 with a Christmas special, followed by the new series in 2017.