After losing 30lbs on a diet of kale and running machines for the Nightcrawler, Gyllenhaal has considerably bulked up for the lead role in the upcoming biopic of (left-handed) boxer Billy Hope.
Southpaw, directed by Training Day director Antoine Fuqua, is currently in the post-production stages. Fuqua told Deadline: “I had [Gyllenhaal] training twice a day in the boxing ring, he did two-a-days seven days a week".
It's a weight gain reminisent of DeNiro's role as Jake LaMotta in Raging Bull, or Christian Bale's transformation from The Machinist to the first Batman film, and adds to Gyllenhaal's credentials as a serious actor, rather than "that guy from Prince Of Persia."
In fact, so great was Gyllenhaal’s dedication that the actor is rumoured to have broken up with his girlfriend over his relentless training regime.
We’ll find out if it was worth it when the film is released next summer.