After being corseted up in Downton Abbey, Cinderella and the BBC's current hit adaptation of War & Peace, it's hardly surprising that Lily James landed the lead role as Elizabeth Bennet in Pride and Prejudice and Zombies, a horror-comedy riff on the Jane Austin classic.

Lily James leads the predominantly British cast

But she wasn't too sure she wanted to be involved. "When I saw the email from my agent," she says, "I was like, 'This sounds terrible!' Then 10 pages into the script, I thought, 'This is so cool!' Somehow these two worlds join together, and it's a riot. It shouldn't work, but it does."

Intriguingly, she was happy that the iconic story has now been overrun by the undead. "I would never have attempted to do Liz Bennet in just another movie," James says. "Why? It's been done so well before. But this is just so incredibly different. It's zombies! We had total license, every single one of us in this film, to not try to recreate, or feel afraid of stepping on anyone's toes or being compared. It ended up being so much fun. So now I think that period dramas just need zombies!"

And she also enjoyed the chance to train for the action sequences. "When I did Downton, I became like a sort of podgy little sludgy thing," she laughs, "because you don't really need to exercise. So it's been really good getting fit. This has been awesome. Yeah, I feel like I can sort of get into some fights now and be a little bit more victorious."

The movie also offered her a chance to costar with Matt Smith, whom she's linked to off-screen. "He just made me laugh all the time," she says of filming their scenes together. "It was great that he had to propose to me."

But while she has enjoyed the costume dramas ("I love all that in-at-the-hips, out-with-the-tits!"), James says she's ready to do something else now. "Actresses I loved growing up, like Kate Winslet, I remember them in things like Titanic and all that kind of period stuff. So that was definitely something I aspired to and I wanted to do myself," James says. "But now having done it so much, I'd quite like to do something where the style doesn't confine your choices and your emotions and the freedom to just sort of let everything out. I'm looking forward to doing something not period."

Watch the trailer for Pride and Prejudice and Zombies: