Jake Gyllenhaal talks physical transformation in 'Southpaw'

As Jake Gyllenhaal's latest film "Southpaw" heads into its second weekend, he's hoping for another knock-out performance at the box office.

In the film, Gyllenhaal plays a boxer whose fights are fueled by anger. When his rage gets the best of him, he loses his wife and his daughter, and he has to figure out how to get his life back.

Gyllenhaal underwent a huge physical transformation to be as believable as possible.

Entertainment Guru George Pennacchio talks to the star about preparing for the role.