The Killing of a Sacred Deer: Plot, Cast, Ending & Where to Watch

Colin Farrell

Farrell, in his second collaboration with Yorgos Lanthimos after The Lobster, delivers Steven's lines at the same off-kilter register the director uses across his English-language work — affect flattened almost to the floor, sentences landed without the rhythms of natural speech. The casting matters because Farrell can carry the weight of a man whose entire identity is competence; when his surgical authority fails to translate to the family crisis, the performance does not raise its voice. It hollows.

Nicole Kidman

Kidman plays Anna with the same controlled stillness she brought to Eyes Wide Shut, which Lanthimos has cited as a touchstone, and she lets the ophthalmologist's professional poise be the first thing the film strips. Her late scene with Martin — calm, transactional, terrifying — is the performance's hinge: Anna's willingness to negotiate suggests she understood the mechanism faster than her husband did, and Kidman plays it without telegraphing the realisation.

Barry Keoghan

Keoghan's breakout role and the engine of the film's dread, Martin is delivered in a register that sits between teenage awkwardness and ritual prosecution. Keoghan, who would later turn the same uncanny precision toward The Banshees of Inisherin and Saltburn, gives Martin a smile that never quite seals and a politeness that never quite reaches the eyes. The performance was nominated for the British Independent Film Award for Best Supporting Actor.

Raffey Cassidy

Cassidy, who had played the young clone in Tomorrowland two years earlier and would go on to anchor Brady Corbet's Vox Lux, holds Kim's adolescence and her crush on Martin in tension with the film's deliberately glassy register. She sings the same song Martin teaches her in a hospital bed with a flatness that should not work and does. The role establishes Cassidy as one of the few young performers comfortable inside Lanthimos's directorial vocabulary.

Sunny Suljic

Suljic, a year before Jonah Hill's Mid90s would make him a recognisable face, plays Bob as the first member of the family to collapse and the one Lanthimos uses to introduce the mechanism. The performance is small and physical: a child losing motor control, dragged across linoleum by his father, refusing food at the dinner table. Suljic anchors the film's most distressing image without overplaying any of it.

Bill Camp

Camp, the American character actor whose late career has been built on quietly excellent supporting turns in The Night Of, Joker and The Queen's Gambit, plays Steven's anaesthesiologist colleague Matthew with the steadiness of a man who has been around operating theatres long enough to know when to stop asking questions. His handful of scenes establish the surgical-world rules Lanthimos will later violate, and Camp gives Matthew the institutional weight the film needs in its early scenes.