For over a decade, the image of Tommy Shelby—the razor-capped, cigarette-smoking patriarch of Birmingham—has been etched into the global consciousness. But according to Steven Knight, the creator and lead writer of Peaky Blinders, the man behind the blue-eyed stare is the furthest thing from a “psychopathic gangster.” The disparity between Cillian Murphy and his most famous role is so vast that Knight often describes the transformation as something supernatural. It isn’t just a performance; it’s what the creator calls a “chilling physical possession.” The Note That Changed History In 2013, when casting for the lead role began, Steven Knight was famously torn between Jason Statham and Cillian Murphy. Initially, Knight leaned toward Statham, worried that Murphy—who is famously soft-spoken and slight of frame—didn’t possess the “brutal physicality” needed for a gang leader. Cillian, sensing the hesitation, sent Knight a now-legendary text message: “Remember, I’m an actor.” That one sentence changed everything. Knight realized that Murphy wasn’t going to play Tommy; he was going to become him. To prepare, the lifelong vegetarian famously began eating meat again and underwent a grueling strength-training regime to “bulk up” his silhouette. This ensured that Tommy appeared imposing even when standing completely still. “That’s Not Acting” Steven Knight and the cast, including the late Helen McCrory and Paul Anderson, often spoke about the “unsettling” atmosphere on set the moment Cillian “switched” into character. “In real life, Cillian is gentle, thoughtful, and incredibly private,” Knight remarked during the production of Season 6. “But when he puts on that coat and that cap, something happens to his eyes. It’s not just acting; it’s physical possession. The air in the room actually gets colder.” This “possession” was most evident in the way Murphy altered his voice—dropping it an octave into a low, menacing rasp. He also changed his gait, which he modeled after the idea of a “tired soldier” who had seen too much in the trenches of WWI. The “Oppenheimer” Factor and the Final Return As of December 2025, the world is eagerly awaiting the final chapter of the Shelby saga. Following his Academy Award win for his performance in Oppenheimer, Cillian has returned to Birmingham one last time for the upcoming feature film, Peaky Blinders: The Immortal Man. Now 49, Cillian recently reflected on spending a “quarter of his life” as Tommy. He noted that returning to the role in 2025 felt like “stepping back into a haunted house.” Steven Knight has teased that in the movie, which takes place during World War II, the transformation is even more extreme. Tommy is no longer just a gangster; he is a man fighting for the soul of the country. A Legacy of Contrast The brilliance of Cillian Murphy’s work lies in the silence. While other actors might rely on shouting or overt aggression, Cillian’s Tommy Shelby is a masterclass in stillness. He once told the Radio Times that he intentionally chose to make Tommy “unblinking” to emphasize his lack of fear. As Knight put it: “The magic of Cillian is that he can go from a man you’d want to have a quiet cup of tea with, to a man you’d run for your life from in the blink of an eye.” When The Immortal Man hits theaters in March 2026, audiences will witness that “possession” one last time. For Steven Knight, it remains the greatest trick an actor has ever pulled off in front of his eyes.