Jharrel Jerome says he skipped lunches on the set of the Anthony Robles wrestling biopic ‘Unstoppable’ in order to work out. The actor tells PEOPLE about transforming into the athlete, who worked his way to a NCAA championship in 2011 despite being born with only one leg.

Born with one leg and a 2011 NCAA championship winner, Robles, 36, is played by Jharrel Jerome in the biopic based on his 2013 memoir, while Jennifer Lopez plays his mother Judy. Bobby Cannavale, Michael Peña and Don Cheadle also star. As Robles tells PEOPLE, “It's a star-studded cast.”