Actor Mark Wahlberg had to put on dozens of pounds to take on his role as a bodybuilder for his upcoming movie Pain and Gain.

Wahlberg had to put on the extra pounds for the bodybuilder role as Daniel Lugo from 165 pounds to 210 pounds.

The Fighter actor gained over 45 pounds in muscle, which he described as painful.

He spoke to ET Online about his intense training for the role. "I was...[eating] ten meals a day. Plus, the weight gainer and all this stuff, it was fun for two weeks because the first movie I did, I had to really get thin, but after that it was like, 'No more!'"

Wahlberg had to eat chicken for the protein he needed to help retain his muscle mass. "[I ate] loads of chicken - pounds of chicken," he said. "I would eat at least two rotisserie chickens a day myself."

He spoke to Access Hollywood at the Pain & Game premiere in Miami on Thursday. "I had a huge preparation. And then also just letting loose, becoming this character. I was always fascinated with the world of bodybuilding." The actor also told them that his sons loved his new look while his daughters didn't.

Wahlberg is set to star in the fourth installment of The Transformers. Filming is expected to start in a few weeks.

Check out Wahlberg's new ripped bod when Pain & Gain arrives in theaters April 26.

Watch the trailer for Pain and Gain below: