Cillian Murphy’s account of Barry Keoghan’s arrival on The Immortal Man set paints the kind of picture actors rarely forget. It was not just another rehearsal, not just another talented performer stepping into a dark crime world already packed with heavyweights. According to the story, Keoghan brought something far more dangerous and electrifying: total disorder. And for a film rooted in the violent, haunted universe of Birmingham’s underworld, that may have been exactly what it needed.
Murphy describes the moment as a turning point. Keoghan was originally meant to enter the rehearsal, deliver a threat, and exit. On paper, it sounded simple, controlled, and functional. But Keoghan apparently had no interest in giving the safe version of the scene. Instead, he detonated it. In a shocking move, he grabbed a glass ashtray and smashed it against his own forehead, sending fake blood down his face in a way so convincing it froze everyone around him. The cameras were not even running, but the room instantly became his.
That is what makes the story so powerful. The most unforgettable performances are often not the cleanest or most technically polished in rehearsal. They are the ones that make everyone else feel slightly unsafe, slightly uncertain, and completely unable to look away. Murphy’s description suggests that Keoghan created exactly that atmosphere. Leaning inches from his co-star’s face, whispering lines in a breathless, unsettling improvisation that stretched for three minutes, he transformed a routine scene into a psychological ambush.
What stands out most is Murphy’s choice of words. He did not frame Keoghan’s energy as reckless for the sake of attention. He called it a chaos the production “desperately needed.” That reveals something deeper about The Immortal Man. In a world like the Shelby empire, brutality alone is not enough. The threat has to feel unstable. It has to feel like violence could arrive from anywhere at any second. Keoghan’s improvisation seems to have captured that exact quality: feral unpredictability, the kind that cannot be neatly choreographed.
For Murphy, who has carried the burden of Tommy Shelby for years with controlled intensity and icy precision, Keoghan’s arrival appears to have offered the perfect counterforce. Tommy is dangerous because he is measured, disciplined, and strategic. A character played this way by Barry Keoghan, however, sounds dangerous because he is impossible to calculate. That contrast is pure dramatic fuel. One man rules through control; the other threatens to destroy the room simply by refusing to be controlled.
The image of a rehearsal stopping cold while everyone watches a bloodied Keoghan whisper through a scene that no longer resembles the script feels almost mythic already. It is the sort of story that instantly builds anticipation around a role before audiences have even seen the finished film. If Murphy’s recollection is accurate, then Keoghan did more than win the part. He announced, in one terrifying burst, that he was about to become a nightmare for the entire Shelby clan.
In a franchise built on menace, style, and raw nerves, that kind of entrance is not just memorable. It is exactly the kind of madness that can change the temperature of the whole story.