Corenswet's physical trainer breaks down the routine that helped the formerly svelte actor put on 40 pounds of muscle—and how he got Nicholas Hoult prepped for Lex Luthor.

Superman doesn’t live in Philadelphia, but actor David Corenswet has called this region home for most of his 32 years on this planet. The new superhero star takes the national spotlight this week in James Gunn’s reboot of "Superman,