Dwayne Johnson discusses voice transformation and physical changes for his role as Mark Kerr in ‘The Smashing Machine’

Dwayne Johnson, known for his action-packed roles, faced a unique challenge in his portrayal of former UFC star Mark Kerr in the upcoming film ‘The Smashing Machine’. Johnson worked closely with director Benny Safdie and co-star Emily Blunt to bring Kerr’s story to life, and the physical and emotional transformations he underwent were central to his performance. One of the most notable challenges was changing his voice to reflect Kerr’s soft-spoken and gentle demeanor, which contrasted with his imposing physical appearance. Johnson worked with voice coach Liz Himelstein, who guided him to speak from the throat, creating a softer tone. Additionally, Johnson underwent extensive prosthetic makeup and gained weight to better resemble Kerr’s athletic build. The transformation process included daily hours spent in makeup and a physical training routine to match Kerr’s unique physique, described as a mix of a sprinter and a wrestler. The emotional preparation was equally demanding, with Johnson noting the importance of trust and vulnerability in creating an authentic portrayal of Kerr’s journey. Early reviews from film festivals have been positive, and the film is scheduled for a wide release in North America on October 3, 2025.