Peter Capaldi has praised the Doctor Who Christmas special for harking back to the days of vintage superhero films, describing modern superhero movies as "grim".
The actor will return in his leading role of the Doctor in the festive episode, entitled The Return of Doctor Mysterio, alongside returning cast member Matt Lucas and newcomers Justin Chatwin and Charity Wakefield.
The theme of the Christmas Day episode is that of classic superheroes, with Justin taking on the role of a mysterious figure known as The Ghost.
Peter said that the script reminded him of the early Superman movies and that fans will be enthralled with the comedic elements to this new Doctor Who outing.
He compared it to current superhero films, of which there has been an endless flow in recent years with Marvel and DC Comics leading the charge.
He said: "When I first read the script I thought 'this is wonderful' because it captures the delightful, light comedy touch that existed in the early Superman movies with Christopher Reeves.
"Superheroes nowadays tend to be a grim lot - but in those days there was optimism and a deliberate naivety that the character of Superman had which was very attractive.
"But also the way the scripts were written back then reminded me of Spencer Tracy or Katharine Hepburn kind of scripts - they were very witty, very knockabout, very American."
He said: "This script is like that so I was very happy to read it and to go with this whole idea of the Doctor observing a superhero - it's great fun."
Peter, who has played the Time Lord since 2013, said the plot for the upcoming episode is "very much a light-hearted superhero romp".
Show creator Steven Moffat said he wanted to do a superhero story for the Doctor Who Christmas special because he loves the "secret identity" they have.
He said: "I like the daft superpowers, I like scenes where the two identities being managed by our hero are clashing with each other - they did that beautifully in the Christopher Reeves Superman films and the Tobey Maguire Spiderman movies.
"That's what's interesting, that's the cool part and you have a certain joyful levity in how you deal with the superpowers because they're fundamentally silly - you can't take them too seriously and I think the Superman movies do that so beautifully."
The episode will see the Doctor join forces with the masked superhero, played by Justin, in New York for a typical Doctor Who adventure.
Matt reprises his role as the affable but bumbling Nardole after first appearing in the sci-fi programme for last year's Christmas special, The Husbands of River Song, and Charity joins as investigative reporter Lucy.
The unlikely foursome join forces to save the city from brain-swapping alien, and the truth about The Ghost - otherwise known as Grant - will also be revealed.
Of Justin, Peter said: "Justin as The Ghost is amazing because he's able to do both of those parts - The Ghost and the mild-mannered Grant - and he's got two different voices that he uses for them.
"I think comic lightness is a greatly undervalued thing - to be as funny as he is and light but with accurate delivery. He has great charm, a movie star quality which is lovely.
"The Ghost is a slightly flawed superhero and he's spot-on with all of that."
Doctor Who: The Return of Doctor Mysterio will air on Christmas Day on BBC One at 5.45pm.