Michael Fassbender has revealed he watched YouTube clips of Sir Ian McKellen to prepare him for the latest X-Men movie.

Both actors play the same character, 'Magneto', in the film X-Men: Days Of Future Past. He plays young Magneto to McKellen's older version.

He joked that he stole all his acting tricks from him: “I stole everything from him. I actually didn’t get to do a scene with him but I spent a lot of time watching him on YouTube giving a workshop on Shakespeare.”

Initially Fassbender was worried about the jumping time frame in the film and thought it might not weave seamlessly together.

“That was something that worried me when I had the script before. There are so many characters, whether there would be clarity and a through line of each of their journeys,” he explained.

But he was very happy with the end result. “It’s definitely an original piece. What I was really happy and surprised with is how clearly and how well both time frames interweave.”

Both attended the film's UK premiere in London last night.

Fassbender says there are violent scenes in the movie, but he doesn't think they go too far: