Although Hugh Grant is currently embodying more villainous characters, he suggests that he’s always had a bit of a wicked side.

His breakthrough role as a romantic lead in the 1994 film “Four Weddings and a Funeral” contrasts sharply with his latest character—a sinister figure who intimidates two Mormon teens in the horror flick “Heretic,” hitting theaters this Friday. Before his rise to fame with “Weddings,” Grant starred in Mike Newell’s next film, “An Awfully Big Adventure,” where he played a predatory theater director.

“Have you seen that film? No one has, and I don’t hold it against you,” Grant, now 64, jokes. He describes his character as “horrible” with yellow fingernails from chain-smoking, comparing his performance favorably to his more well-known romantic lead role. “I remember thinking, ‘I’m much better at this than in that ‘Four Weddings’ movie.’”

In “Heretic,” Grant portrays the cardigan-wearing Mr. Reed, who is reminiscent of his previous antagonistic roles, such as the self-absorbed Phoenix Buchanan in “Paddington 2” and the mischievous Oompa-Loompa in “Wonka.” He lures the sisters Paxton (Chloe East) and Barnes (Sophie Thatcher) into his home, promising them blueberry pie and deep discussions about faith, but ultimately subjects them to a complex and torturous ordeal.

“We included photos of my younger self with a dog and ‘Bless This Mess’ displayed to placate the girls. I aimed to come across as genuinely nice as long as possible,” Grant says. Then things become increasingly bizarre.

Grant’s attention to detail is described as a unique strength by Scott Beck, who co-directed “Heretic.” He observes, “Hugh constantly pushes himself to grow, especially in the past twelve years as he takes on more character-driven roles.”

In this discussion, Grant shares his inspiration for “Heretic,” his exploration of the horror genre, and hints at returning to romantic comedy with “Bridget Jones: Mad About the Boy,” which will stream on Peacock starting February 14.

Question: What drew you to Mr. Reed?

Answer: I was intrigued by the opportunity to portray him as an unconventional professor with an eccentric twist. I imagined him at a mediocre university in the U.S., sporting an English accent, glasses, and denim attire, attracting a following of young women. I pictured him hosting seminars where students viewed him as a sort of prophet and hypothesized that one of them might have met a tragic fate, raising concerns among the university officials. They didn’t terminate his position; they merely asked him to leave quietly. I know those kinds of teachers.

Would your younger self, the well-liked leading man, support your transition to character roles?

I believe he would. “Four Weddings” was a massive success, and while I’m grateful for the romantic comedies that followed—most of them are enjoyable films beloved by audiences—I do wish I had also explored that darker side more consistently. My last major dip into that was in “Restoration,” a lesser-known film featuring Robert Downey Jr. where I played an arrogant character with noticeable beauty spots. That marked the end of my “monster Hugh” period until about six years ago.

What triggered this change?

The shift was gradual. My entire romantic comedy career took a nosedive in 2010, leading to a dry period. Gradually, opportunities emerged where I could indulge my desire to portray eccentric characters. Films like “Cloud Atlas” showcased this, and certainly in the series “A Very English Scandal,” where I portrayed politician Jeremy Thorpe. Even in a comedy like “Paddington 2,” my character is quite monstrous.

What are your thoughts on your first horror film, the 1988 release “The Lair of the White Worm”?

The actors were quite puzzled by it. Just a couple of nights before filming began, we had a read-through that made us all laugh uncontrollably. We later realized that (director Ken Russell) was sharing in the laughter too. It seemed he wasn’t entirely sure whether to take it seriously or not. Regardless, the end result is delightfully bizarre. The scene where (Amanda Donohoe) hurls venom at the crucifix is simply brilliant.

Was portraying Daniel Cleaver again in a new “Bridget Jones” a nice change from Mr. Reed?

I guess so. I’m even starting to think, “Wait a minute, Hugh, you’ve spent so many years doing romantic comedies. Don’t fall into the trap of playing just sinister characters one after another.” (Laughs) So you’re right; it’s at least a refreshing shift from that. The challenge with bringing Daniel back. well, first, he’s dead, which is always a hurdle.

That’s true.

And then there was the character of Daniel Cleaver from the first two films, a charming womanizer. I was quite concerned that in his 60s, his character might not come off as fun anymore, but rather distasteful. Yuck. So, I dedicated a significant amount of time collaborating with various people, including (“Bridget Jones” author) Helen Fielding, to develop a new backstory for him and explore what transpired during the years to add more depth to his character.