From writer/director Derek Cianfrance and based on the award-winning novel of the same name by Wally Lamb, the six-part HBO limited series I Know This Much Is True follows identical twin brothers Dominick and Thomas Birdsey (played in two stand-out performances by Mark Ruffalo) on their own very different life paths. It’s a family saga of sacrifice and forgiveness which begins in their present — the early 1990s — and digs into different stages in their lives as it highlights how mental illness affects everyone, including the person directly dealing with it.
During the virtual press day for the limited series, actress Kathryn Hahn, who plays Dominick’s ex-wife Dessa, spoke to Collider for this 1-on-1 phone interview. During this chat, we spoke about why this project was an actor’s dream, exploring the soul connection between Dessa and Dominick, how Cianfrance empowers his actors, and the most challenging day of the shoot. She also talked about how this is a pretty exciting time in her career, how she’d really like to get to explore the horror genre, and her love of The Babadook.
COLLIDER: When you came across this character, did you get excited about the chance to emotionally dig deep?
KATHRYN HAHN: Yeah, this was an actor’s dream. It was so juicy, and I was so moved by the material. I had a deep personal connection to the material, as well, as so many families do, with mental illness, empathy, and family. Especially coming off of the other projects I had been working on, the idea of playing this particular woman, who’s so connected to this man that has betrayed her in such a profound way, and to be able to still see the force of forgiveness, I knew it was gonna be an interesting deep dive for me, to be able to find that, and it did not disappoint. It was definitely a juicy actor’s dream.
Your work in I Know This Much Is True is terrific, as was your work in the last HBO series you did, Mrs. Fletcher. Is there an enjoyment in playing a character where you’re getting to explore them for longer than the life of a movie, but also not having to do so for an endlessly ongoing amount of time?
HAHN: Yeah, there is. Derek [Cianfrance] and Mark [Ruffalo] both looked at this as one long movie, so that’s what it felt like. Even with Mrs. Fletcher and I Love Dick, there was something so fun about having the breadth of working and having a little bit of a longer space to be able to uncoil all of the possibilities of who these people are. I don’t like to come into anything too pre-planned. I do a ton of work beforehand, but I don’t wanna have anything set because you find it so much in the other person’s eyes and in just being in the space that your fellow artisans have made for you, in terms of the set and the props and the costumes, and being with your director for the first time.
This limited series space really appeals to me, in those creative ways, because you can take your time for things to land and simmer, in a way that sometimes you don’t have in a feature, or maybe even an open-ended series, where things are being written as it’s happening. It’s hard to control that, or fit into it. Especially with something like this, you know that the given circumstances from the script are impossibly painful and they’ve gone through such unimaginable trauma together, and I also knew that it was gonna be a bobbing in and out of the story, so I knew that it was gonna be a great challenge to able to try to find that history, every time I would land in the scene with him, coming back and forth from L.A. to New York, but Derek and Mark made that so easy. As difficult as it was, the vibe was so collaborative and so empowering.
This could have been a very tricky character in a film because, as the ex, her backstory would probably be the first to get cut for time. But we really get a sense of who she is, and the background between these two people and what they went through. I really appreciated that.
HAHN: Yeah, me too. They’re so profoundly and deeply soul-connected. I had the time to really work through with the two of them —meaning Mark and Derek — what that trajectory was. It was important to us there was an opening, at the end, but that it not be completely romantic or platonic. We wanted just a glimmer of possibility, but who knows what their next chapter is gonna look like. The way Dominick felt about Thomas, I felt that way about Dominick. I just felt a profound need to take care of this person. I just could see the potential in his heart, from the very beginning. All of the crap he was putting on himself, and the weight and the victimizing, I could feel very clearly through to his possibility and potential. As an actor, that was a real different thing for me to play with, to walk into somebody who had that kind of breadth of forgiveness and openness and optimism in the face of such unbelievable trauma.
What was Derek Cianfrance like as a director during the shoot? Did you guys talk a lot about this during the filming of it? Or is he someone who lets his actors do what they need to do, unless there’s a reason to guide them, in some way?
HAHN: We talked a lot about it, but it didn’t feel micromanaged or over-thought or intellectual, which is my favorite kind of actor-director talking. Everything felt very essential and about what these people wanted and needed. There wasn’t a lot of intellectual talk. It felt very empowering. He would ask a lot of questions, which I really love. He would get us, as actor, talking and he’s an incredible listener.
For you, what was the most challenging day or scene on this shoot?
HAHN: I would say the scene with their child was pretty difficult. That day was pretty difficult. We only had a few days to shoot in that house, so we had to do all of those scenes at once, and there was a lot. We had to go from the honeymoon period to when she leaves him, so that was a really intense few days. I don’t know if I would say it was difficult, as much as I would say it was like jumping off of a cliff, emotionally. But the vibe of it never felt precious. When we had to get to work, we got to work, of course. I knew Mark was not gonna leave anything on the table (and he didn’t), so to be able to bear witness to that was pretty extraordinary. But it didn’t feel quite as weighted as you would think, in that environment, just because it was so much. I was able to go into the house a little bit beforehand and rearrange the furniture put things in places, and memorize where everything was in the house and make sure that I put my fingers all over everything. That’s an actor’s dream, to really feel that texture.
Are the little things like that, the things you like to do, as an actor, to help you find the character?
HAHN: Yeah, for sure. It’s not intellectual and it’s not talking it to death. It’s just something can seep in, and then you can let it go. When you’re in the scene, all you really need is your partner in front of you. In this case, it was just looking at Mark Ruffalo as Dominick. I found most of it in just looking at him. Even if you don’t know, as an audience member, that kind of stuff adds texture and history and weight. I think all that stuff is really important.
You’re playing such an interesting variety of characters, from I Know This Much is True to Mrs. Fletcher to the animated musical series Central Park. Is this a time in your career that has been particularly exciting and fun for you?
HAHN: Yes. I never could have thunk, in a million years, it would have landed this way. Doing [Central Park] was such a blast with those incredible musical gods. That was a dream and also wholly unexpected. I don’t understand it. I don’t know how. It feels like chaos. It’s really crazy that I’m able to do these wildly different genres and wildly different things. I don’t take any of it for granted. I know how easy it is to be pigeonholed. I just feel really weirdly lucky that I’ve been able to escape under the radar and flip around. That’s been a real joy. That’s why I wanted to do all of this, in the first place, back when I was a kid, putting on plays. Being able to jump into so many different genres and being asked to do so many different things has been a real joy. I don’t take it for granted.
Is there a genre that you’d still love to work in, but haven’t gotten the opportunity to do yet, or you feel like you haven’t gotten enough of an opportunity to do yet?
HAHN: I really love horror. I love it, love it, love it, love it, love it. Doing The Visit was so fun. I would love to do another straight-up horror. I love that genre, so much. That would be so fun. Comedy horror is my fave. This is not a comedy horror, but I just saw The Babadook again recently and I love that movie. That would be a ball. It’s so interesting; the genre is just the starting point. I just love that I’ve been asked to do these juicy, complicated, messy things, that I feel like are asking more of me that I had been asked to do, in my 20s. That’s a real unexpected thrill. For someone post-two children and in her 40s, it’s buoying to know that’s possible.
I Know This Much Is True airs on Sunday nights on HBO.