"I never thought that I would be the shirtless guy in a scene," says the actor of a transformation that was "not only physical but spiritual'

By Mia McNiece
Updated July 07, 2015 01:25 PM
Credit: Courtesy El Rey

For the second season of From Dusk Till Dawn: The Series, Wilmer Valderrama said he wanted to create a whole new look for his villainous character Carlos Madrigal.

“I wanted him to come back more dangerous,” Valderrama tells PEOPLE. “I thought doing a full-body transformation would be exciting for the character.”

So, five months before filming in Austin, Valderamma began hitting the gym twice a day for early morning and evening workouts. He also stuck to a strict nutrition plan consisting of five small meals a day of protein, lots of greens and healthy carbs like yams and brown rice.

“I had to put chocolate, burgers, pizza and my ranch dressing on hold,” says the That ’70s Show alum, 35, who adds that the hard work was well worth it when he put on 10 lbs. of muscle.

“I never thought that I would be the shirtless guy in a scene,” he says. “When they released the first still from the new season, it was a little embarrassing for me, and I got a little shy, but the fans were really sweet about it.”

Valderrama says in the process of changing his body, he also changed his mind.

“The transformation was not only physical but spiritual, too. Things got a little more clear, and my ambition for business and for other things definitely grew.”

Also enjoying his new physique is girlfriend Demi Lovato, 22, who plays a crucial role in the show’s second season.

“She came to play with us in the season finale,” he says. “She is a very talented young woman. She kicked ass and did great.”

WATCH: From Dusk Till Dawn: The Series‘ Exclusive Season 2 Trailer

From Dusk Till Dawn: The Series

premieres Aug. 25 at 9 p.m. ET on El Rey Network.