Arn Murphy on Youth, War and Taika Waititi's Klara

At 19, Arn Murphy has already carved a small, intriguing path away from simply being "Cillian Murphy's son." He appears in two HBO dramas—Youth and War—and landed a role in Taika Waititi's Klara and the Sun. Suddenly, a name that might once have been a footnote has become a headline on its own.

In a recent chat with Variety, Arn talked about the strange, accelerating arc of those early roles, the mentors who made space for him, and the quiet gravity of growing up with one of cinema's most watchable actors as his father. "I don't even think we're that similar," he said with a laugh, "but apparently other people disagree." Short sentence. Honest one.

In Youth, Arn plays Rauri, a withdrawn young man who walks away from university and returns home after a rumor upends his life. The story toys with perspective—what really happened, and can we trust the narrator? Arn enjoys the ambiguity: "Yes—I like to think he's innocent. But that's for the audience to decide. Still, I want to back him."

There was a real overlap between actor and role. Both Arn and Rauri were at that fragile, decisive age: 18, recently out of school, asking whether university was the right move or some other life should begin. "That moment of having to choose—it's when you start dipping a toe into adulthood," Arn said. That shared uncertainty became the quickest route into the character.

Working with Sharon Horgan on Youth helped sharpen that path. Arn praised her pragmatic, collaborative approach—"charismatic, open to ideas," he said—adding that the script's strength made it easy to find chemistry with the rest of the cast. When a script is confident, actors can be brave. They can discover nuance rather than manufacture it.

War offers a different terrain. Arn plays Gabriel, a boy trapped in the turbulence of his mother Carla's divorce—Carla played by Sienna Miller—and the volatile household with stepfather Morgan, played by Dominic West. Gabriel becomes collateral in a messy feud between a washed-up actor and a social-media billionaire. Anger is everywhere in that world. "Everything was in the script," Arn observed. "His frustration, the lack of release—people just want to let their anger out." Short. True.

Acting didn't feel inevitable to Arn. For a while he pictured himself on the football pitch. Then, at 11, a school play changed the map. That experience, he said, crystallized the desire to perform when the right time came. He grew up watching his father work—one memory that sticks is seeing Ken Loach's The Wind That Shakes the Barley at eight. Heavy stuff for a child. "Seeing my dad in those dramatic moments at that age felt intense. Maybe I should rewatch it now that I'm 19," he joked.

He has seen many of Cillian Murphy's films, but not all. What matters more than the filmography, Arn said, is what his father offered at home: stability, guidance, and a steady presence. For Arn, Cillian's greatest role has been the quiet, supportive dad—not the celebrity or the screen legend. Living beside someone used to scrutiny, he added, makes the spotlight feel less novel and more manageable.

Klara and the Sun, shot in New Zealand when Arn was 16, felt surreal. "One minute I was in school, the next I was flying off to work with Taika Waititi," he recalled. On set, he learned from Jenna Ortega and Amy Adams—actors he describes as generous and kind. The experience, he said, was an education more than a credit.

And yet Arn is cautious about some of the industry's future tools. He isn't a fan of artificial intelligence in entertainment and doubts it will benefit the industry overall. At the same time, he thinks Klara and the Sun will fuel useful conversations about AI and what defines a meaningful life—friendship, love, and the messy qualities that make us human.

For now, Arn is auditioning, learning, and hoping for projects that let him keep growing. His trajectory feels deliberate rather than leveraged; the choices suggest curiosity more than convenience. Klara and the Sun is slated for release on October 23, 2026. Will audiences watch Arn step out from under a famous surname and meet him on his own terms? That question is part of the fun.