Théodore Pellerin and Archie Madekwe in Fame Game

“I’m not a fan,” snaps Matthew, the master manipulator in the guise of a harmless nobody eager to soak up some of the refracted rays of celebrity in Lurker. Once he has penetrated the inner circle of emerging pop star Oliver, a fan is the most insulting thing you could call him. Proximity gives Matthew — played by Théodore Pellerin with an evil innocence from which you can’t look away — the illusion of being a best friend, a bro, a creative collaborator to the mononymous singer. Everyone in his entourage wants to bask in Oliver’s glow, but nobody wants it as badly as Matt.

Alex Russell, a writer on The Bear, Beef and Dave making an assured feature directing debut, clearly knows the Los Angeles music scene, with its aspirational strivers and anointed supernovas, its hangers-on, its calculating opportunists and, yes, its lowly fans for whom an all-access backstage pass is the holy grail. Even the chosen few lucky enough to secure a spot in a star’s immediate orbit are subtly jockeying for position.

Played by the sensational Archie Madekwe with the beatific aura of a chill narcissist who only gradually reveals the cracks of self-doubt, Oliver is an L.A. transplant from England on the precipice of greater fame. His discarded surname might not be just an affectation but a severance of all ties from the mother he won’t talk about. “I have a new family now,” he tells Matthew early on, with the glint in his eye of a man knowingly dangling a carrot. “And I get to choose who’s in it.”

Matthew lives with his grandmother (Myra Turley), gets around on a bicycle and works as a sales assistant in an L.A. hipster clothing boutique frequented by celebrities. When returning customer Oliver comes into the store, Matt casually switches the music to a mellow Nile Rodgers groove, which we get the feeling he knows is a favorite of Oliver’s. They chat, and while being careful not to fawn, Matthew strategically puts himself on the singer’s wavelength. Matt’s colleague Jamie (Sunny Suljic) jumps in to say he’s a major fan, but it’s Matt who gets invited backstage for Oliver’s show that night.

When Matthew gets there, the vibe with inattentive Oliver and his entourage is not what he expected. Two of the guys in particular, Swett (Zack Fox) and Bowen (Olawale Onayemi), delight in putting Matt on the spot and mocking him. But he’s intuitive enough to pass their test.

Russell is adept at authenticating the dynamic in this core group, who make a joke of their suspicion toward newcomers. Their responsibilities are mostly vague — shrewdly observant Shai (Havana Rose Liu) seems to be Oliver’s manager and sometimes girlfriend; Noah (Daniel Zolghadri) is the tech guy working on social media fodder and documentary footage; Bowen is the studio mix engineer; and Swett sits around playing video games and cracking wise.

After the performance, Matt somehow manages to say the right things, again without gushing, and Oliver invites him back to his crib, an airy rental in the Hollywood Hills. Matt starts hanging there every day, and even though he’s lowest on the pecking order and treated like a housekeeper, he finds ways to ingratiate himself with Oliver. He shows some skill shooting Oliver at play with his grandma’s old camcorder (“Whoa, that’s some Spike Jonze shit!”) and soon, he’s put in charge of the documentary and asked to take photographs for Oliver’s upcoming album cover.

Despite appearing to be an unworldly geek, Matt knows how to play the game, measuring the flattery with tweezers at times and with a trowel when required. He says Oliver inspires him to be creative and feels they met for a reason. “I think you’re going to be the biggest artist in the world,” he tells him. Of course that’s exactly what Oliver wants to hear, especially since he’s feeling stuck in his music and impatient to move up to the next level. It also gingerly plants the idea that Matt can somehow help him get there.

Noah, prickly about his role being usurped, tries to maneuver Matt back to the margins, but the infiltrator won’t be deterred. An apparent mishap on a music video shoot gives Matthew the advantage and tips us off that he’s either following a plan or extremely lucky. But the hint of a Jennifer Jason Leigh in Single White Female-type in Matt’s large, globular eyes soon becomes unequivocal.

The movie arguably takes a little too long to kick in, but once its sense of danger — devious, disturbing, wryly amusing — is established, it never stops. The visuals acquire a scrappy vitality from the video interludes and the mood is enhanced by Kenneth “Kenny Beats” Blume’s rangy synth score.

The turning point comes when Matthew invites Jamie to tag along to a party at Oliver’s house and instantly regrets it when the group takes a shine to him. Talented DP Pat Scola, who shot Pig, Sing Sing and A Quiet Place: Day One, locks a visibly annoyed Matt in needling closeup as Oliver and company compliment Jamie on his DIY sweater and he generously suggests they send him their sizes so he can make one for each of them.

It’s exactly the kind of smart move Matt recognizes, but he underestimates Jamie’s resourcefulness and is quietly seething when his boutique co-worker is invited to fly with them to London, where Oliver is performing. Matt is more skilled than Noah at sidelining a rival, getting Jamie out of the way not once but twice with shady moves that don’t get past watchful Shai. Even before they leave London, Matthew finds himself iced out.

Desperate, obsessive and determined to force his way back into Oliver’s circle, Matt orchestrates an opportunity by setting up the singer in a legally compromising situation. That gets captured on the surveillance camera he installed in a corner of the living room ceiling, ostensibly to shoot B-roll. The precision with which some of Matt’s machinations play out occasionally stretches credibility. But it makes sense that Matthew would be able to anticipate Oliver’s behavior, given how much time he spends studying videos of him.

The film’s switches into low-key thriller mode once Matt reveals who he truly is, gaining the upper hand and using it like a born blackmailer. The extreme discomfort around Matt of Oliver and his crew adds a creepy undercurrent to the action. The knot gets wound tighter each time anyone tries to remove him from the equation, notably in a scene loaded with homoerotic tension, in which Matt insists that Oliver wrestle him on the bedroom floor, his cackling pointing up just how unhinged he is beneath his studied composure.

While many movies would reach this point and deliver a suitable comeuppance for the interloper, Russell is not interested in that obvious outcome, even as violence explodes. The director is more intent on showing how, despite the barriers usually in place to police obsessive fandom, even the most seemingly unattainable position can be within reach to someone sufficiently cunning and driven to reinvent themselves.

The whole excellent cast is on the same page, but I especially enjoyed charismatic Abbott Elementary regular Fox, who straddles the line between laid-back and surly with appealing ambiguity; Liu, whose Shai is cool-headed, decisive and nobody’s fool; and Zolghadri (very funny in another well-received Sundance entry, If I Had Legs I’d Kick You), who nails both the self-defense reflex and the bruise of being one-upped. The movie’s portrayal of male competitiveness is super-sharp.

Given that we experience the story from Matthew’s perspective, there’s both complicity and alarm in watching his scheme unfold. Pellerin — a gifted Quebecois actor known for Never Rarely Sometimes Always, the short-lived Kirsten Dunst Showtime series On Becoming a God in Central Florida and the 2023 queer drama Solo — is nuanced enough never to play him as a straight-up villain. He’s more of a borderline psychotic outsider with his eye on the prize, not content with the hand life has dealt him. The gangly physicality of Pellerin’s performance also helps keep us guessing about how far Matt will go and whether his victories will hold.

By contrast, Madekwe (seen in Midsommar and Saltburn) is silky-smooth, making Oliver a man who has carved out a significant comfort level in his own skin, even if his insecurity as an artist sometimes intrudes on his swagger. (The actor very capably does all his own soulful, hip-hop-inflected vocals.) In the standout scene where Matt definitively turns the tables, Madekwe is wrenching, his character’s long-simmering anger giving way to tears of defeat. At least in that moment.

There’s a dark strain of humor in the mere fact that it’s never clear whether Matt — an Eve Harrington hiding in plain sight in the early scenes behind the mask of a socially awkward loser — genuinely even likes Oliver’s music, or any music at all. The final-act developments might seem a little too tidy, but the closing scene is a marvel of icy cynicism and wit in its cautionary depiction of the perils of fame and the lengths some will go to feel the warmth of the spotlight.