Peter Capaldi has praised his Doctor Who colleague Matt Lucas as being "one of the biggest and most talented comedy stars" the UK has ever produced.
Peter, who stars as the Doctor in the hit BBC series, will appear alongside Matt as Nardole in the forthcoming Christmas special.
Matt is reprising his role as hapless Nardole after first appearing in last year's Christmas episode The Husbands Of River Song.
He has also been confirmed to be appearing in the tenth series of Doctor Who when it airs in the spring.
During a Q&A session on Twitter, Peter praised Matt, who is best known for co-creating and starring in sketch show Little Britain.
Asked what it is like working with him, Peter said: "It's absolutely wonderful because he's one of the biggest and most talented comedy stars that the UK has ever presented.
"If you think of all those character he has created - the gay in the village, Vicky Pollard, the chap in the wheelchair and all that stuff - and he's lovely.
"He's just an absolutely great person to have around and he makes me laugh all the time, and I think you're going to really enjoy him in Doctor Who."
The actor added, jokingly: "Is it him who asked this question?"
Peter and Matt will return in The Return Of Doctor Mysterio, which airs on BBC One on Christmas Day.
The 60-minute show will see Peter as The Doctor teaming up with an investigative journalist, played by Charity Wakefield, and a superhero named Grant, played by Justin Chatwin, to save New York from a deadly alien threat.
During the social media Q&A, Peter also revealed his love of Doctor Who started in his childhood and was in part due to his proximity to a Tardis-style police box.
He said: "I was drawn to the magical, strange quality of it all, and it seemed to me that Doctor Who could also show up in your own world, the Tardis could arrive in your own street.
"When I grew up in Glasgow they still had police boxes and there was actually a police box at the end of my street."
The Return Of Doctor Mysterio airs on BBC One on Christmas Day at 5.45pm.