“We could put it out in black-and-white, and you would think it was William Hartnell,” he continued. “There’s new monsters, there’s new jeopardy. But what’s fascinating is the First Doctor confronting the superhero he’s going to become, with his supersize TARDIS and all that.”

Bradley has recently revealed at the London Film & Comic Con that he and outgoing Doctor Peter Capaldi are set to clash over their attitudes toward women during Steven Moffat’s final episode.

“What we did emphasise,” Bradley explained, “was the old fashioned nature and how he is from the 60s. He goes into the Twelfth Doctor’s Tardis and says ‘it’s a bit dusty around here, it’s in an awful state isn’t it? Where’s Polly? Shouldn’t she give it a spring clean?’ And then Peter’s saying ‘you can’t say that’.”

Bradley added that his character “brings all his 60s sensibilities, what’s lovingly called casual chauvinism. He’s just talking [as if] the [companions] are there just to help out, and do the dusting and do all the domestic chores – his attitudes to a lot of things come right from the 60s, so there’s a lot of conflict between Hartnell’s Doctor and Peter’s Doctor about how things have changed in the last 50 years… we had quite a bit of fun with that.”

It looks like the First Doctor might get a bit of a shock if he sticks around until the end of the episode, but Bradley’s new revelations seem in keeping with the themes current Doctor Who showrunner Moffat spoke about recently when generally describing Twice Upon A Time. He told TV Guide that Capaldi’s swansong will explore what his Doctor “stands for, what he tries to be, the man he aspires to be”.