Actor Jake Gyllenhaal was a changed man after training for the upcoming sports drama film "Southpaw".

The 34-year-old underwent extremely rigorous training to prepare to play Billy Hope, a boxing champion who's attempting to get his life back on track, but the tough regimen didn't just transform him physically, reports eonline.com.

Gyllenhaal went from a relatively slight 147 pounds to a ripped 175 pounds in just six months, trainer Terry Claybon, who whipped Jake into shape for "Southpaw", said. And they had a lot of work to do when they first met up to discuss training.

"He wasn't in any shape at all. We met at a boxing gym, and he was jumping rope. Just the way he was jumping rope, I knew we had a lot of work to do,` Claybon said.

"Everything we did in training was as if he was having a professional boxing match,` he added.

The film is slated to release on July 24.