A few years ago, author Wally Lamb’s agent asked him who would be the ideal actor to play the twins in an adaptation of his bestselling novel “I Know This Much Is True.”

Lamb didn’t hesitate: Mark Ruffalo.

With that in mind, Lamb’s agent sent the tome to Ruffalo in the hopes he’d be interested in starring in it.

Ruffalo remembers reading the book and “how moved I was, how, in a strange way, it felt familiar to me, my Italian family .. Just how beautifully it was written – I mean, I assumed that this was Wally’s autobiography; it was just so specific and visceral. I immediately, as I was reading it, thought, ‘I have to be part of making this.’ It touched me in such a way. The characters, the connection between two brothers – it’s not a story you see often. When you do, it’s pretty powerful. It’s so fraught, there’s so much drama … He really captured the sense of jealousy, of resentment, of feeling responsible. It’s a very rich place to draw (from).”

Ruffalo did end up starring in the HBO limited series version of “I Know This Much Is True,” and he drew rave reviews for his dual performances — along with an Emmy win for outstanding lead actor in a limited series or movie.

Ruffalo will be at the Garde Arts Center in New London next week for the first movie-theater screening of the series, which premiered on HBO in May of 2020.

The plan had been to do some screenings of it in theaters in early 2020, but the pandemic prevented that. Lamb resurrected the idea this year, and so two episodes of “I Know This Much Is True” will be shown at the Garde each night from Wednesday through Sept. 23.

Lamb, Ruffalo and director Derek Cianfrance will be at the events on Thursday and Sept. 23 to talk about the project. (Lamb will be there by himself on Wednesday.)

“I Know This Much Is True” centers on twins Dominick and Thomas Birdsey. Dominick is a divorced house painter who feels responsibility for his twin, who has schizophrenia, but also deep resentment. The novel opens on a scene of Thomas cutting off his own hand at a public library, which he says is a sacrifice to God to prevent the Gulf War. The narrative jumps back and forth in time, delving into family trauma and secrets.

Discussing his work on “I Know This Much Is True” during a phone interview on Thursday, Ruffalo says, “At some point, I really did think, ‘I’ve bitten off way more than I can chew.’ Just Dominick alone by himself is a really difficult character and then not to mention the uncharted territory of (Thomas) and his mind and how to do that honestly. I did really at some point have my doubts that I’d be able to pull it off.

“I mean, Derek by design gave me six weeks between ending one (character) and starting the next, ending Dominick and starting Thomas, that I had enough time to really prepare it, but, yeah, I was exhausted. By the time I finished Dominick, I was exhausted, and then I had to go forward and try to put together Thomas, which I hadn’t been able to use any of my bandwidth on. It was really scary, and I really didn’t know how I was going to pull it off.”

Playing someone who struggles with schizophrenia, as Thomas does, was challenging and complicated.

“It was such a dark, dark place, that interior life is so dark. … It’s so confusing. There’s this sort of battle between ‘Is this real, or is this not real?’ Each moment has these kind of ‘Am I seeing a person there always in my periphery — is that real, is that not real?’” Ruffalo says.

“It’s always sort of on alert. It’s just actively looking for danger all the time, the nature of it, the tangential thinking — those are the qualities that I noticed from watching people in schizophrenic episodes, hearing people talk about it themselves, reading about it, and from spending time with someone who is living with schizophrenia, just trying to effect all that and bring some semblance of my imagination into it. It was really hard to do.”

He adds, “So much of it is this kind of interior chaos, and it’s so negative for Thomas … Those voices and those thoughts are so negative.”

An act of generosity and love

While Ruffalo was Lamb’s first choice as an actor, Cianfrance was Ruffalo’s first choice as a director.

“I thought him doing this material would just be really special,” Ruffalo says.

He asked Cianfrance to read “I Know This Much Is True,” and then they went for a long walk together to talk it over. Ruffalo recalls that Cianfrance was very reticent because of the twin aspect of it.

“He felt like (with other films in which one actor plays two roles) he always saw just an actor going and putting a mustache on and then coming back. And he didn’t want to do CGI. He’s just a very honest filmmaker, and he doesn’t want to do any of those kinds of tricks, (things) he sees as tricks,” Ruffalo says.

Then Ruffalo suggested they do something similar to what happened on the HBO series “The Normal Heart” that Ruffalo was in. Production shut down for four months so that Matt Bomer, who played a character dying from AIDS, could lose weight.

Ruffalo pitched it this way: “That’s how I’m seeing this, Derek. We’ll shut down, I’ll go and change. I’ll grow my hair, we’ll change him, so it’s just different. … (Thomas) is physically different, and you’ll know that’s a real beard, it’s not a fake beard, that’s real hair.”

Ruffalo planned to first lose weight to play Dominick and then gain weight to play Thomas.

Cianfrance liked that idea. And he took it step further.

He wanted for Ruffalo to play opposite a great actor, so when Ruffalo was Dominick, another performer would be playing Thomas. Ruffalo recalls Cianfrance saying he wanted to bring in someone who is “going to give you just as much off-camera as you are putting on camera. I wouldn’t want it to be you speaking to a tennis ball or you having to have someone, a PA (production assistant) off to the side reading your lines, or a script supervisor. I want a real actor there who’s going to give it to you with just as much passion and commitment as you gave you performances in the original piece.”

So Cianfrance brought in actor Gabe Fazio, who really dove into his performances — which, of course, never made it onscreen.

“It’s too bad you can’t see that performance because that’s as good as anything I did and just as committed,” Ruffalo says.

Fazio even lost weight to play Dominick and gained it to play Thomas, just like Ruffalo did.

“To do what he did was an immense act of generosity and love,” Ruffalo says.

k.dorsey@theday.com

IF YOU GO

What: Screenings of “I Know This Much Is True”

Where: Garde Arts Center, 325 State St., New London

When: 7 p.m. Wed. hosted by Wally Lamb; 7 p.m. Thurs. and Sept. 23 with Lamb hosting an audience chat with star Mark Ruffalo and director Derek Cianfrance

Cost: $24 for Wed., $48 for Thurs. and Fri.

Contact: (860) 444-7373, gardearts.org