I Know This Much Is True: Mark Ruffalo Shines in Playing Identical Twin Brothers–HBO, May 10

Mark Your Mark Ruffalo Emmy Ballots

Mark Ruffalo plays identical twin brothers, Thomas and Dominic, defined by very different personalities and different issues in HBO’s I Know This Much Is True.

An adaptation of Wally Lamb’s 1998 best-selling novel, the limited series centers on Dominic and Thomas Birdsey and the many trials they go through, with Dominic trying to look out for Thomas after he’s committed to a mental-health facility.


Director Derek Cianfrance wrote all six episodes of the series, which premieres on May 10.

The show begins with a shocking act: Thomas Birdsey enters a public library and amputates his right hand.

In the course of the series, which is tough to watch, Ruffalo alternately fights, comforts and runs after himself.

Cianfrance captured the tricky and challenging series with shrewd camera placement, CGI effects, and a six-week production shutdown. Ruffalo, after shooting for 17 weeks as Dominick, went away to gain 30 pounds in order to return as Thomas, who, among other problems, has schizophrenia.

The show is Cianfrance’s first series, after directing some indie features (“Blue Valentine,” “The Place Beyond the Pines”), and the first for Mark Ruffalo in two decades.

The actor logged onto a Zoom meeting from his house in upstate New York.

Motivation to do a series?

Ruffalo: My wife is an avid show watcher. She turned me on to it. I was jealous that actors were getting to really dig into characters. But there’s a continuity in having one director and one writer, which I insisted on from the very beginning. Derek and I have always talked about it as a six-hour movie, and we shot it that way.

Too many catastrophes?

Ruffalo: I didn’t think there was enough. I was just so moved by it. It was personal in a lot of ways. I lost my brother, Scott, in 2006.  That will always be something that I’ll draw from. We were almost Italian twins, a year apart from each other.

Challenge of playing twins?

Ruffalo: I’ve always been a little crazy. I’ve always bit off more than I can chew, as a form of self-destruction. But some part of me also is willing to meet the challenge as best as I can.

We didn’t want it to feel like I would shoot Dominick and run and put on a wig and shoot Thomas.  I knew that HBO would conceivably let us shut down production so I could gain weight. We really wanted to create two separate people that were so distinctly different from each other, even though they were identical.

Dominick, he’s the favorite son, brought up in a very masculine way. We couldn’t find Dominick’s character until Derek told me to do 50 push-ups between each take. That became how we grounded Dominick–very upper body, very tense, very aggressive. Thomas has a mental illness, living with schizophrenia, but he has emotional facility that’s alien to Dominick.

Research about schizophrenia?

Ruffalo: That was the most daunting thing for me. We tried some iterations of it along the way; none of it was working. But I got to know someone who was living with schizophrenia. One thing about YouTube and social media is that you can get to know people who are living with this, they speak so openly about it. I probably watched 1,000 hours of people living with schizophrenia.  We tried many different versions of Thomas.  Finding the personality of Thomas was the most difficult part of it.