Considering Benedict Cumberbatch’s intense schedule of film, theatre and TV roles, you’d think his time would be pretty tight by now. But as it turns out, while filming new Marvel superhero movie Doctor Strange the actor managed to squeeze in an entirely separate second role alongside the titular sorcerer – and nobody noticed, until now.

You see, while developing the film’s ultimate villain Dormammu (an extra-dimensional energy being) director Scott Derrickson realised that there was only one person to bring him to life – the guy he already had on set in a big cape who had plenty of experience with motion capture.

"We knew [Dormmamu] was an all CG character, but as we were in production Benedict brought it up as an idea,” Derrickson told IGN. "He said, 'What would you think about me doing it?' I said, 'Let me think about it, you know.'"

"It's an interesting idea, because I did fancy the idea that as this other-dimensional being he's not moving through the Dark Dimension, with a countenance, with eyes and a face, eyes and a mouth, and a human visage – why would he? He takes that form on to communicate with Strange."

So after a bit more consideration, Benedict was roped in to play his character’s worst enemy, providing the facial motion capture while another actor (who Derrickson couldn’t remember) supplied the voice.

"The more I thought about it the more I liked the idea," Derrickson said. "Because no one understood Dormammu better than Benedict did. I also wrote that role to be a kind of ultra-inflated version of Strange. He is an ego run amok; he is this cosmic conqueror where everything, where literally everything in the multi-verse is about him.

“There's something interesting about this confrontation of this little, tiny guy who has this power of time and this monstrous conqueror who is trapped by a clever gambit. There's something about that worked well, and I didn't think anybody to interact with Benedict than he, himself."

So there you have it – Benedict Cumberbatch plays both hero AND villain in Doctor Strange, and we’re envious of his scheduling skills. Maybe he ended up pocketing that time-bending Eye of Agamotto after all…

Doctor Strange is in cinemas now