Mare of Easttown's mother-son duo on keeping the show's heartbreaking twist secret

Warning: This post contains spoilers from the season finale of Mare of Easttown.

In the end, Erin McMenamin's (Cailee Spaeny) killer had been under Mare's (Kate Winslet) nose the whole time: Her best friend's son, Ryan (Cameron Mann), had found out that his father was sleeping with Erin, and when he went to scare her off using a neighbor's gun, she fought back. Ultimately, Erin's death was an accident, but it resulted in Lori (Julianne Nicholson) losing her son.

EW has the exclusive interview with the mother-son duo at the heart of Mare of Easttown's mystery: Julianne Nicholson and Cameron Mann.

ENTERTAINMENT WEEKLY: What has been you all's experience with the audience reaction to this ending?

JULIANNE NICHOLSON: How are people feeling about it being you, were people surprised?

CAMERON MANN: Yeah, people that find out are really surprised. They never thought it would be Ryan. I tell them I'm an actor but they didn't know that I'd have such a role on the show.

NICHOLSON: I've had mostly positive reactions like Ryan did it. People seem to be happy with that outcome. I personally am relieved that it wasn't Lori, the jealous wife, who killed the teen girl, so that was a great relief to me. But then you have to deal with the tragedy of your son's life being ultimately taken away. It's a mixed bag but people seem to be really satisfied by the conclusion, which is always the tricky thing.

When did you all meet for the first time?

MANN: I'm not sure it was the first time but we went to dinner in Philadelphia.

NICHOLSON: Yeah we went out to pizza, me and Cam and his lovely mom Jill. We got on right away.

MANN: Yeah.

NICHOLSON: It felt very easy from the very beginning. I have a son who's Cameron's age. Cameron loves basketball but my son loves soccer and Cameron's a reader so I think I gave you a book that my son had read?

MANN: Yeah, and the T-shirt.

NICHOLSON: The Philadelphia basketball T-shirt!

MANN: [Spending time together] was really important.

NICHOLSON: Really important but very easy because Cameron's just a nice guy. He has a similar temperament to my son, which is just like open and generous and sweet. So it was very, very easy to care about him and what happens to Ryan immediately.

MANN: You just made me feel really comfortable in that environment and that was really important because your character, as my mom, she was the person that Ryan was closest to and we had some heart-wrenching scenes together.

Julianne, I know you knew Kate before this, but Cameron, had you ever met her?

MANN: I did not know her personally but the first time I met her was when I came to get the Ryan Ross haircut. She called me to set and took the time to meet me and talk to me and she was asking me if I was ready for it. When Kate Winslet asks you that, the only thing you can say is, "Yes." [Laughs] That was really awesome. She made me feel so welcome and safe.

At what point did you know that Ryan was the one who killed Erin?

MANN: The scenes for the initial audition didn't really reveal much about the character but I knew Kate Winslet was starring in this so I knew it was pretty big time. Initially I didn't know that my character would be such a big part in the show. We got episode 7 just before filming started, and I'd read the other six episodes but I had no idea that this plot twist was coming. Knowing I would play such a key role was super exciting. And much like Ryan I also had to keep it secret for a very long time. No one knew except for my parents.

Was it hard to keep that secret from friends?

MANN: It was because I have so many friends at school who kept asking me to tell them who the killer was. Obviously, I wasn't just going to tell them that it was me. I wanted them to watch the show and find out for themselves.

NICHOLSON: That must've been so hard! I like barely see people so a few people asked me and I just listened to who they thought it was but I didn't have to deal with friends pressuring me every day. That must've been really hard for you!

MANN: Yeah. My siblings too.

NICHOLSON: Your siblings! Your siblings didn't know?!

MANN: No. We're living in the same house, so it was pretty hard to keep that from them.

NICHOLSON: Woah! That is a secret! I was so relieved when episode 7 aired.

Which of your scenes together sticks out as the most memorable for you?

NICHOLSON: For me it was the scene where he comes in and says, "It's Mare. She knows." That was the biggest scene for me that we had together and the most heart-wrenching. I didn't find it difficult to get to that place. Even talking about it, I feel like I remember that moment and hearing his voice catch and the terror in his voice. I found it so unbelievably awful just imagining that scenario. For me that was our most memorable scene together.

MANN: Yeah I totally agree. At that point during shooting we were already close so I could really see you as actually being my mom and that made it easy to get into character to film a scene with so much emotion. Another scene I think was really hard was the interrogation scene. When I read the script for it and saw what I had to do, obviously I was so grateful to be doing the scene with you guys. You, Kate, and John Douglas Thompson, who played Chief Carter, really made me confident I could pull off the emotional power the scene needed.

NICHOLSON: You have a lot to do in that scene, to find the truth in that confession.

MANN: I'm pretty sure it was originally written as mostly voiceover as well. I pretty much had to learn it right before we filmed it.

NICHOLSON: Oh that's right i remember that! Surprise!

MANN: That was a little stressful.

NICHOLSON: I have to say Ryan came with such a quiet confidence. Everybody fell in love with him from the moment he walked onto set. I feel like he looks like he could be my son — he doesn't look like my son but he looks like he could be my son — and there was never any doubt that the audience at large would fall for him too. To watch him throughout the series and then have all this work to do in the end I think was a real huge payoff that we knew would be there but I can imagine for any actor, nevermind a young actor, that that could be rather weighty. You nailed it.

MANN: So did you! I learned so much from Julianne and Kate and I'm so grateful and honored to have worked with them and also [creator] Brad [Ingelsby] and [director] Craig Zobel and to be part of a show that has become such a hit.

In the end, we find out Ryan's been keeping this huge secret this entire time. How do you feel like it impacted him?

MANN: When you find out Ryan was at the center of the mystery you learn that he's been holding in this secret the entire time, which is probably part of why he was so quiet but there were also outbursts of anger, like the cafeteria scene and the interrogation scene, where he lets it all out.

NICHOLSON: Someone said to me, "Actually it's the best thing that Ryan was found out because now it's open, there's support to help rehabilitate people, therapy, all of this." As opposed to, if he was never found out and he had to keep that secret and the family had to keep the weight of that secret, what does that look like on a person as they get older? I thought that was such an interesting take on it.

MANN: Yeah I think Ryan was feeling panicked but also some relief. Mare did kind of help him because that secret was really torturing Ryan. He knows that no matter what his mom loves him unconditionally. But that's also what's so heartbreaking when he's taken away in the police car without her. It's like his childhood is ending right there because his mom can't fix this.

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