Adam DiMarco gets under your skin in his new horror film 'Undertone'

WHEN ADAM DIMARCO joined our Zoom call for his interview, the actor kept his camera off. He hinted that it was because he had just moved house and perhaps the set-up wasn’t quite “set up” enough to show on camera. I thought it a clever conceit, a nod to his latest film, Undertone, the new horror film from writer-director Ian Tuason. In Undertone, DiMarco is heard more than seen, playing Justin, the co-host of a paranormal podcast whose presence reaches the film through voice, suggestion, and steadily mounting unease. Speaking to him as a disembodied voice, with no face to read and no expression to confirm tone, felt like an extension of the film’s method.

“But I never really like hearing my voice when I’m talking,” DiMarco casually drops. “Sometimes when you do a podcast or some radio interview, there’s that option to hear your own voice being fed back into your ears or just going without? I always go without.”

It’s a fascinating confession given that his character in Undertone is all voice. That challenge was part of the appeal. DiMarco says he had done voice work before, though he had not always prioritised it. Early in his career, on-camera jobs won out. More recently, after The White Lotus, he did an Audible audio series based on Edith Wharton’s Glimpses of the Moon, which helped open that side of the craft up for him. By the time Undertone arrived, he says it felt surprisingly natural. “It felt the same as on-camera work, to be honest. It felt very naturalistic. And Ian was open to ad libbing, and it just felt really fun and collaborative.”

Still, naturalistic does not mean passive. One of the more interesting things DiMarco says about the role is how physical he remained while recording it. Without facial expression or body language to lean on, he compensated by creating movement around the microphone. “I would start a scene by walking into a room and sitting down at a chair and moving my things around,” he says. Even during booth pickups, he tried to keep that sense of motion alive. “It’s tough to act without your body.” There is a practical intelligence to that answer. It gets at something actors do not always say plainly: voice is not a separate instrument from the body. It is the body, translated.

That matters in Undertone because Justin sits in a delicate place within the story. The film follows Evy, a paranormal podcast host who returns to her childhood home to care for her dying mother. When Justin sends her a series of ten mysterious audio files, the sounds begin to break through the boundary between recording and reality, pushing the film into something far stranger and more invasive. The audio dimension is not a gimmick here. Tuason reportedly began with a 250-page audio-cue script before the film was remixed in Dolby Atmos, building a horror film where sound is not accompaniment but structure.

Without giving away where the story goes, Undertone works because it understands that listening can be more destabilising than seeing. Personally, it is one of the few horror films I think is better watched at home than in a cinema. A cinema always has an exit point. At the end, you leave. Home is home. The film becomes immersive in the truest sense because it leaves the viewer in the same rooms, with the same dark corners, with the same low-grade suspicion that the next sound might not belong to the house at all.

Asked if DiMarco ever saw Justin as deceptive, even if the film invites that reading, he said he preferred to lean into ambiguity. “I never saw him as an unreliable narrator,” he says, explaining that he understood the character’s history with Evy and the degree to which he was on her side. But he also recognises why audiences might project doubt onto him. Horror, after all, tends to demand someone you are not sure about. What interests him more broadly are characters who sit in murkier territory. “I really like morally grey characters,” he says. “It’s very rare to find someone who’s just white or black. Most people are grey.”

That has become a useful through-line in his career. He hit the mainstream as the earnest Albie Di Grasso in season two of The White Lotus, playing a young man whose apparent decency gradually reveals its own blind spots and self-interest. More recently, he has also been part of Overcompensating, Benito Skinner’s college-set Prime Video comedy, where he plays Peter Whitney, a campus golden boy who conveys all the toxicity of the stereotypical frat boy, but you get the feeling that it’s a deflection from deeper issues. In both shows, as in Undertone, he is drawn to characters who are readable at first glance and more complicated once you spend time with them.

Asked whether comedy or horror comes more naturally, he does not make a big theory out of it. “I feel like I try to approach both of them just from a natural place,” he says. “I’ve been lucky to be blessed with good writing.” Fair enough. That is probably the most useful thing to know about DiMarco right now.

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