Hugh Grant spent half his career in rom-coms. Now he plays monsters, and he’s never been happier.

NEW YORK — After some difficulties connecting to a Zoom, Hugh Grant eventually opts to just phone instead.

“Sorry about that,” he apologizes. “Tech hell.”

Grant is no lover of technology. Smart phones, for example, he calls the “devil’s tinderbox.”

“I think they’re killing us. I hate them,” he says. “I go on long holidays from them, three or four days at at time. Marvelous.”

Hell, and our proximity to it, is a not unrelated topic to Grant’s new film, “Heretic.” In it, two young Mormon missionaries (Chloe East, Sophie Thatcher) come knocking on a door they’ll soon regret visiting. They’re welcomed in by Mr. Reed (Grant), an initially charming man who tests their faith in theological debate, and then, in much worse things.

After decades in romantic comedies, Grant has spent the last few years playing narcissists, weirdos and murders, often to the greatest acclaim of his career. But in “Heretic,” a horror thriller from A24, Grant’s turn to the dark side reaches a new extreme. The actor who once charmingly stammered in “Four Weddings and a Funeral” and who danced to the Pointer Sisters in “Love Actually” is now doing heinous things to young people in a basement.

“It was a challenge,” Grant says. “I think human beings need challenges. It makes your beer taste better in the evening if you’ve climbed a mountain.”

“Heretic” is directed by Scott Beck and Bryan Woods, co-writers of “A Quiet Place.” In Grant’s hands, Mr. Reed is a divinely good baddie — a scholarly creep whose wry monologues pull from a wide range of references, including, fittingly, Radiohead’s “Creep.”

In an interview, Grant spoke about these and other facets of his character, and his journey from rom-com idol to horror-film villain.

AP: Do you have any theories on why horror has been so popular in recent years?

Grant: It’s fascinating, isn’t it? I don’t know. Maybe these are the end of times, the end days, the apocalypse. We know it deep down but for some reason we won’t confront it. I don’t know, but it’s wonderful that it sends people into the cinemas.

AP: Have you seen many horror films?

Grant: I can’t. They’re too frightening for me. I watched “The Exorcist” when I was too young and I’ve been in counseling ever since. I watched one by mistake recently, which was “Midsommar.” I thought it looked like a jolly, Swedish comedy. I put it on one evening for my Swedish wife who needed cheering up and she’s still very, very traumatized

AP: You’ve spoken before about your affinity for the big screen. Is the seeming decline of theatrical moviegoing a concern for you?

Grant: It is. Talk about the end of days. To me, one of the gloomiest signs or omens is the gradual closing of cinemas — and not just that, where I live in London, but the closing of bars. The bar where I met my wife, which was party night every night of the week, is now largely closed. I think the fact that we’re all staying in, staring at our devil’s tinderboxes is deeply tragic, or watching things on streaming by ourselves with maybe one or two other family members. These things should be collective experiences.

AP: One element that you’ve said factors into your choice of roles is whether you believe the film will be entertaining. Do you find your gauge for that is still accurate?

Grant: My ability to gauge what’s entertaining, I used to be very proud of it. In the old days, my old career, I used to say, “I’m not so proud of my acting but I’m proud of the fact that the films I’ve done, on the whole, have been entertaining and I’ve been good at choosing them.” And then, suddenly overnight, I became very bad at choosing them. I don’t know, I lost the zeitgeist, I suppose. That can happen. Now, I feel like I’ve found something again.

If the character amuses me and I think I’m going to enjoy being that person, then I tend to do the job. Sometimes, when actors are enjoying it, it works.

AP: When would you mark this shift for you?

Grant: The big shift was after “Did You Hear About the Morgans?” That was sort of officially the end of romantic comedy for me. Nothing much happened after that in showbiz terms. I went off and did political campaigning and I was quite happy, in fact. But in drips and drabs, strange little projects, like the Wachowski’s “Cloud Atlas,” then Stephen Fears came along with “Florence Foster Jenkins” and “A Very English Scandal.” “Paddington 2.” These interesting, complex, often not very nice, narcissistic weirdos started to emerge from the woods.

AP: After this role, it might be hard for you to find something darker…

Grant: I agree.

AP: Does that make you want to push darker still or rebound back in the other direction?

Grant: It’s a very good question that I do not have the answer to. As a matter of fact, there is one thing sitting on my desk in the other room here which is pretty weird and relatively fresh. I agree, I’m not quite sure where to go from here. Maybe it’s song and dance.

Watch the trailer from “Heretic”: