Mark Ruffalodidn’t hold back when it came to transforming into his latest character.

In the show, Ruffalo stars as two very different but identical twin brothers, Dominick and Thomas Birdsey. Theactor filmed all his scenes as Dominick for the first 15 weeks, before taking five weeks off to transform into Thomas.

Thomas is schizophrenic and has been on years of medication, and Ruffalo said he gained weight to accurately portray the effect that can have on someone’s body.

Mark Ruffalo as Thomas and Dominick inI Know This Much is True.Atsushi Nishijima/HBO

Mark Ruffalo I Know This Much is True

“We didn’t want it to be like I run and throw a wig on and do the same scene in the same day, so we took six weeks off to really separate these two guys,” Ruffalo said. “And Thomas is on medication, mood stabilizers and anti-psychotics. A lot of people put on weight.”

“Putting on the weight for Thomas was really challenging,” he added. “I didn’t expect it to be. I thought I was going to have a fun time doing that, but when you’re force-feeding yourself, some of the romance of food sort of leaves.”

Studying his character and what Thomas would have been going through in his life, living with his mental illness, also made those five weeks difficult for Ruffalo.

Mark Ruffalo.

Mark Ruffalo

The Emmy Award-winning actor also admittedhe was scared to play this character,because he knew how important it was to portray him accurately andspread awareness about an “important issue.”

“It means a lot to me to be honest with that, which means going into that world and getting to know it and getting comfortable with it,” he said.

“And that’s challenging, and so that aspect of it was challenging…I was really afraid to play him,” Ruffalo added. “I think it’s really an important issue, and I want to tell it as honestly as possible. The responsibility is on me.”

The miniseries is set to premiere on HBO this April.

source: people.com