David Corenswet takes fans inside his full-body transformation for James Gunn’s Superman, unveiling the physical and emotional toll behind the cape. The video documents his months-long journey with celebrity trainer Paolo Mascitti, where he followed a strict 4,500-calorie diet, performed high-volume gym sessions, and underwent flight training with the stunt team. Between wire rig rehearsals and costume fittings, Corenswet brings humanity to the superhero prep process, making the myth feel real. Paired with insight from Gunn’s production team, this featurette is more than just a fitness reel—it’s a testament to the making of a modern icon.