Hollywood has a long history of encouraging actors to live in the worst possible headspace for roles while also pushing their bodies to the brink. Even actors who don’t try to live as their characters all the time (a process often referred to as Method acting, though that’s not exactly what the Method is) still end up changed by the psychological effects of rigorous physical transformation. Efron certainly felt that. “Having all that weight on, you don’t feel normal,” he explained, “and the delayed-onset muscle soreness was through the roof.”
The actor says that managing his bodily transformation and the impact of a shoot that required real in-ring action changed his social life, saying, “You don’t have to be super social. I found myself withdrawing quite a bit.” Nicole Kidman, who remains friends with Efron after the two co-starred in Lee Daniels’ 2012 film “The Paperboy,” told Variety the actor clearly “put his whole heart and soul into [‘The Iron Claw.’]” She says she “watched him physically and emotionally change to play that role.”