By Clark Collis
April 23, 2014 at 09:28 PM EDT

In the ’70s-set The Quiet Ones, Jared Harris (Mad Men) portrays a British professor determined to prove that there is a scientific explanation for the seemingly supernatural phenomena besetting a young woman, played by Bates Motel actress Olivia Cooke. As The Quiet Ones, which opens this Friday, comes to us from the famously horror-obsessed U.K company Hammer, it does not spoil things too much to reveal that the prof’s plan goes wildly awry.

Below, Harris talks about The Quiet Ones — which co-stars Erin Richards, Rory Fleck-Byrne, and Hunger Games franchise cast member Sam Claflin — and why your guess as to what’s going to happen next on Mad Men is as good as his.

ENTERTAINMENT WEEKLY: This seems to be a horror film where everyone concerned was determined to play it with a straight face.

JARED HARRIS: You had to. I mean, I loved Evil Dead 2. But that’s a totally different type of movie. You’re robbing the audience of the experience if you’re not taking it seriously.

What was it that attracted you to the film?

What I liked was that it dealt with the supernatural but started from the point of view of skepticism. You slowly work away at the audience’s objections and doubts, which are legitimate, until you get to the point where you’ve rationally brought them there, rather than, “You must assume this is true from the very beginning when you buy a ticket.”

When I was growing up in Britain there almost seemed to be a Hammer movie on TV every night…

Yeah, yeah.

…were they a big part of your youth?

We had a 16mm projector and my father (screen legend Richard Harris) used to rent movies for us. He loved Westerns and action films and horror movies. So, yeah, I loved them. We used to watch them all the time, scare ourselves silly. I remember he rented — and regretted it for a long time — Night of the Living Dead. I didn’t sleep for decades.

I think there’s a noble effort involved [in Hammer]. Every weekend, British movies have to compete with American films at the British box office. It’s an uphill mountain every weekend. The goal is to establish an identity, a brand, in British cinema that audiences will come and support. I think Hammer have a tremendous opportunity to do that and the British public hopefully, once they get the idea of what they’re doing, I think they’ll support it. And it’s fun, you know. It’s a fun brand.

What was the shoot for The Quiet Ones like?

It was tough. Those sort of budgets, they require you to do a lot of work in a short amount of time. The good thing on this was that the director (John Pogue) insisted that we would get two weeks’ rehearsal, which was really important because all those sort of séance-type scenes, some of them are long, and they all are shot from one perspective so you can’t cut. [It] was a good opportunity for us all to get together and bond and figure out each other’s playing styles.

Now, you, like me, are still in the first flush of youth…

[Laughs] You old silver-tongued devil you.

…but compared to the rest of the film’s cast you’re something of an elder statesman. What was that like for you?

There’s a great tradition in theater where the lead actor is expected to lead the company. You’re supposed to set an example, but you’re also supposed to protect them, and help them out, and create room for them so that they get heard, their ideas get tried out. On the reciprocal side of that, you can become a little bit frustrated and jaded by filmmaking — there’s so many problems, you can become swamped and forget that actually it’s great fun and it’s a joy to do. I got that off of those four. I said, “I’m never going to forget that ever again.”

The Quiet Ones isn’t your first horror film. What do you remember about making Resident Evil: Apocalypse?

Actually, going back to The Night of the Living Dead, when they sent it along, when I read the bit where I turn into a zombie, I [thought], “I’m in! I want to be a zombie!” Just to purge that fear. But, yeah, great fun.

Mad Men recently started again. Is it odd to have this train go on without you?

I’m a fan. I watched all of season 6 and really enjoyed it. I sit there like everybody else trying to second guess where it’s going and what’s going to happen and loving it.

You can check out the trailer for The Quiet Ones below.