Was it easy to slip back into the character of Erik Lehnsherr?

I'd say no because we'd departed from the Erik character in First Class, so now we're sort of dealing more with the Magneto side of him. So when we pick up with him this time, he's made that transition, and the difference from the first film is that now he's without an army. When we meet him, he's been in prison for many years so he's a bit of a lone wolf in that regard.

How much did Bryan brief you on what he'd been up to in the 10 years we don't see?

Well, essentially he's been locked away! That's where he's been, in solitary confinement under the Pentagon. They have accused him of assassinating JFK, and so they've had him locked up ever since.

Days of Future Past is an iconic storyline for the X-Men comics. You looked at the comics before you made First Class, so did you study up again?

There were a few elements that were changed from the comic books in terms of who does the time travel, so I looked at the comic books again. I still had some of the images and notes that I had taken from the last one, and used those as well. And this time I was looking more at Ian McKellen and his voice than I did on First Class.

The first film was more Erik's journey to becoming Magneto. This is more about Xavier. But how would you describe it?

It’s essentially Charles' journey to become Professor X. In this one, we find a very broken Charles Xavier who, for lack of a better way of putting it, has lost faith in himself. This is about how he finds that strength again and using the bridge between the past and the future that is provided by Wolverine, they set about preventing what's happening in the future.

You have Bryan directing this time, the overseer of the X-Men universe. How was it working with him?

I think especially because the older cast had been reunited, he was the best person to come back. There was an excitement about that before I even arrived to shoot in Montreal… an anticipation, if you will. But the great thing about Bryan is that he's very collaborative and flexible and you have that freedom with him, which is fantastic. And the same goes for (writer/producer) Simon Kinberg.

Bryan has said that there were a lot of things that were changed on set and on the fly. Was that something you appreciated?

Yes, absolutely – because you're always trying to find the best piece of the puzzle. In Days of Future Past you have these two worlds that are moving in parallel in one respect, so to organise that and tell both stories very clearly, that's a challenge in itself. We all worked together on that, and Simon is excellent with this type of structure. Having worked with them on First Class and knowing that they're open to the actors' input helps to make for a great process.

Hugh and others have said the First Class cast had a lot of fun between scenes. Were you trying to keep people in line?

I was in the thick of it! I remember one particular time where I felt like Ned Kelly. Josh Helman, James and Nick (Hoult) had pinned me into my trailer in a BB gun shootout. James was trying to come in through the skylight on the roof and Nick shot me through a crack in the door – it was an excellent shot, actually, he got me right in the neck and it took the wind out of me briefly. So it was a lot of fun. We did wear protective eye wear, it should be noted, so there was safety involved, but there was scarring to the face also, so eventually the BB guns were taken away. It was a purely professional environment! Healthy exercise.

One of the new elements is Peter Dinklage as the new villain. Did you enjoy working with him?

I gelled with Peter immediately. I remember the first day on set – he's incredible, a genius. He's just so funny and obviously an excellent actor, but we more just felt like we were on the same wavelength. I'm just bummed that I didn't have more scenes with him. But watching him work was a pure joy.

First Class was a big film, but in some ways Days of Future Past feels bigger. Did it feel that way on set?

In terms of the scope and story, yes, absolutely – and with a much more complex structure. But I didn't really see it like that, even though I knew the ship was a mothership (laughs).

One particular scene found you on a plane gimbal with James, Nick and Hugh. Was that particularly challenging?

Not really, because I was bolted in there! In terms of making it look like you're naturally standing, yes, because you're on a belt on a pole and you're leaning forward. But the truly hard part was trying to find the relationship beat required because Charles and Erik haven't seen each other in so many years and their feelings towards each other have been pent up for so long. So it was an important scene, given how emotionally invested Erik is in his friend and continues to be throughout the other films. To have that emotional resonance, it was an important one to get right.

Do you and the First Class cast feel vindicated after that film's success? You're the focus of this one, despite the presence of Hugh and the other original actors.

It's such an ensemble piece and has so many layers and strands to it. I feel each time I approach a job that there's a responsibility that comes along with it, so I was so happy that the fans really enjoyed First Class when it came out. You always worry how the core fan base will react, so that was a relief. But you also want to always remember that you're only as good as your last, and the next story is only as good as the last one, so there's always that pressure.

How was it spending time with the whole cast and the original actors at Comic-Con? Was it surreal?

I loved that, mostly because I hadn't met Ian yet. James gets the opportunity to do a scene with Patrick, but I finally met Ian at Comic-Con and it was fantastic to finally get to be face-to-face. He left me a nice note in the trailer on set, saying he was sorry we missed each other again, so that was quite special. And then to have everybody else there, with all of the excitement in that room... it was pretty amazing. Comic-Con is a special festival, the one place that truly belongs to the fans.