Barry Keoghan returns from the bathroom of a “members only” club on the Lower East Side in New York City and plops down a handful of Dubble Bubble in front of me and his girlfriend, Shona Guerin. “Here’s some gum,” the 25-year-old Irishman says. I grab one—not because I necessarily want any, but because Keoghan seems to be presenting the Dubble Bubble as some kind of ice breaker, and it’d be rude not to join in. But as I start to untwist the wrapper, he quickly interjects: “The question is, do you trust me?”

It’s a pretty fucked up thing to say, considering Keoghan knows I’ve just seen The Killing of a Sacred Deer. In the film, directed by Yorgos Lanthimos (The Lobster, Dogtooth) and costarring Colin Farrell and Nicole Kidman, Keoghan plays a teenage boy named Martin who forces the surgeon who accidentally killed his father (Farrell) to make a dreadful compromise: sacrifice an immediate family member, or else watch each of them go paralyzed, bleed from their eyes, and then slowly die. How Martin is able to set off this agonizing chain of events is never explained; Keoghan plays him with an eerie matter-of-factness, blankly reciting the horrific rules to Farrell’s Steven Murphy like they’re lines from a book report. He uses a similar intonation to suggest that he’s poisoned the Dubble Bubble, clearly relishing the layer of wickedness that starring in Sacred Deer has added to his bright-eyed, innocent-seeming persona.

I put the gum down on the table.

Keoghan has had a remarkable few months: Before Sacred Deer, he played George, a naive, pure-hearted teen in a sweater vest, in Christopher Nolan’s blockbuster World War II epic Dunkirk. It was a small role with a basic function and only a handful of lines, but Keoghan managed to capture a sense of idealism in the character—to the point that his sudden death is genuinely and tragically sad. “I always said, I want to work with good indie filmmakers, and if a blockbuster comes up and the filmmaker is great, I’ll do that,” Keoghan says. “And then I get the best of all that! It’s Chris Nolan! The best director who also makes big films.”

Still, Keoghan’s performance in Dunkirk hardly compares to his turn as the Sacred Deer’s grim reaper in blue jeans and a backpack. Sacred Deer is a movie about responsibility, consequences, and comeuppance, and Keoghan’s Martin is the center of gravity around which all of those themes revolve. Lanthimos, as always when it comes to his films, is the one who crafted the seemingly alternate, near-human universe of Sacred Deer—at once sick and sickly humorous—but Keoghan is his mouthpiece, morphing from a simple, sympathetic kid into a merciless but magnetic exactor of justice over the course of two hours. “His face, his physicality, his whole presence,” Lanthimos tells me, when I ask why he decided to cast Keoghan. “He’s just an interesting human being to watch. It would’ve been easy to create this one-dimensional evil kid, but his mere presence conveys many different things at the same time.”

“To get to play those two roles within the space of a few months, to show my range, that’s a dream,” Keoghan says. “I want people to go, ‘Fuck, that’s him? He’s completely different.’”

Keoghan was born in one of the grittier neighborhoods of Dublin, Ireland. He’s from the north side of the River Liffey, which bisects the city and acts as a socioeconomic dividing line between the underprivileged north and the more affluent south. His mother, who was addicted to heroin, died when he was 5 years old, and he was sent to live in foster care. It’s the only segment of Keoghan’s life he won’t talk about; when I ask him about his childhood he responds, “You’ve probably done your research, haven’t you?” as if to say, “The information’s out there, so let’s move on.” When he was 11, his grandmother took him in. He’s more than happy to tell stories from his adolescence, painting a picture of himself to be just as sneakily sinister as some of the characters he’s played. He got kicked out of his all-boys high school because “they weren’t having my games anymore. The last thing I done was, I threw a coin and it hit a teacher in the head. That was the last straw for them.” He tells the story bashfully, staring down at his feet and suppressing a smile.

It was around that time that Keoghan started acting. “I seen this note in a window that said this small Irish movie Between the Canals, they were looking for actors.” Keoghan, who had never acted before, saw an opportunity. “I took the number down on the sly, because I knew that my friends would take the piss out of me, and I rang it when I went home.”

“Acting? I don’t know—I just see money,” Keoghan says when I ask what made him audition for the movie, an admission that feels honest and understandable. Actors are especially known for treating their profession like a craft they were drawn to by Dionysus himself; to hear one flatly admit that it’s a job is both jarring and refreshing. For much of the beginning of his career, Keoghan played characters similar to the side role he landed in Between the Canals: troubled kids from the streets. In 2013, he appeared in six episodes of the fourth season of Love/Hate, an Irish television series about Dublin’s criminal underbelly; he played a homeless youth in 2016’s Mammal. They weren’t splashy parts (Mammal screened at Sundance), but they were enough to get Keoghan noticed.

As Lanthimos says, Keoghan just has one of those faces. It somehow seems to be in constant flux; one second he looks like a Dior model, the next he looks like if Cillian Murphy got hit with a shovel. Sitting in front of me in a white tee and gray, Superdry sweats, he looks kind, innocent, and young—much younger than 25—but his expression can quickly flip, either because the light hit the scar under his right eye in a funny way or because he wants to tease you about poisoning your food. It’s his greatest weapon, and he knows how to use it.

The Killing of a Sacred Deer is full of disturbingly memorable scenes, but one stands out: About two-thirds through the film, Stephen Murphy’s wife, played by Kidman, confronts Martin in his home and begs him to lift the curse. Martin’s in his boxers and in the middle of eating a plate of spaghetti, which reminds him of a story about his father. As a kid, Martin remembers, he used to marvel at the way his dad ate pasta: so efficient, so brilliant. He demonstrates, twirling some of the pasta around his fork and eating it in one big mouthful. Still chewing, and with sauce covering his face, he continues the story, blankly recalling how devastating it was to grow up and one day realize that the way his father ate pasta is the way everyone eats pasta. The discovery made him feel betrayed, Martin says; as if the man whom he revered so much barely even existed. Meanwhile, Kidman’s character sits across from Martin dumbfounded, realizing how deep the boy’s scars go and perhaps coming to grips with the fact that the person who holds her life and her children’s lives in the balance is a teenager covered in marinara sauce.

It’s an outrageous scene, this kid shoveling spaghetti into his face while spouting an allegory about coming to realize your own insignificance—and Keoghan is unflinching, turning each forkful into a work of art. “You know, sitting in front of Nicole Kidman in your boxers is not an easy thing to do,” Keoghan tells me, hardly interested in talking about his performance or how he’s able to simultaneously capture pain, loss, and bald evil in one fell swoop. “I was just constantly like, ‘Can she see up there?’”

On the day we meet, Keoghan’s particularly giddy because Aaron Paul tweeted about how good he was in Sacred Deer. After six years of toiling away in mostly Irish productions, Keoghan’s performance as Martin has put him in a position where he can not only think about the future of his career, but the next five or 10 years of his life in general. Keoghan says, “It’s all a plan.” When he first signed with his talent agency, WME, this plan was already partially formulated: He had written down a list of directors he wanted to work with. Christopher Nolan and Yorgos Lanthimos were both on it. “I write everything down,” he says. “Directors, movies I want to do, that I want to produce, direct, start my own company, start my own boxing club.” Keoghan takes his roles in Dunkirk and Sacred Deer as proof that the first step to achieving a goal is putting it down on paper (or in his iPhone Notes). “I’m a big fan of the law of attraction,” he proudly states. He won’t show anyone the obsessively curated and growing list, but everything on it can be boiled down to one simple goal: “Have a successful, good career.”

Keoghan seems to know that, at 25, after two prominent roles in the films of two high-profile directors, his plan is coming together. He has two upcoming projects on his slate—an Irish movie starring Hugo Weaving and Jim Broadbent called Black 47, and American Animals, costarring Blake Jenner and Evan Peters—but he wants to ride this momentum even more. “I’m lookin’ for that script,” he says, leaning into the recorder, graveling his voice to sound tougher. “I’m lookin’ for that script!”

His personal life shows a different side of him, one that’s less scrappy and not so firmly tuned to survival mode. You might even call him a romantic. He met his girlfriend, Shona, at a bar she worked in in Kerry. He asked her out on the spot, but not to dinner or anything like that: He suggested they drive out to Dingle, a picturesque peninsula on the west coast of Ireland. “Luckily she had a car. I had no way to get to Dingle,” Keoghan notes. Two weeks later, he returned to Kerry with suitcases. They’ve been living with Shona’s mom since.

“He doesn’t put a lot of thought into things,” Shona tells me, with more admiration than admonishment. “But he’s very caring. He can feel when he’s done something wrong. It hurts him.”

Now Keoghan and Shona want to move to the United States. They don’t know where exactly—he prefers New York City, she prefers L.A.—but the idea of turning ex-pat is thrilling to them. “And we’re looking to get our own dog,” Keoghan adds. “A rescue one. I know it sounds ridiculous, but I just love them, don’t I? They just listen.”

“I have to try to be in the moment,” Keoghan says at the end of our interview. “Because these moments we’ve been having lately are great. Everyone is looking at you, and it’s like, you’re totally in control of everything. It’s something that you need to enjoy.”

I pick up the gum again, and Keoghan’s eyes follow me as I put it in my coat pocket. He says nothing this time. Walking away from the table, I pull out the gum and decide to eat it.