Did you get a chance to talk to Amy at all about Camille?
Lillis: I unfortunately didn't really get a lot of time to speak with her, especially because we're the same person. She's doing a lot. She's very busy. She's in a lot of scenes. I never really got to talk to her a lot. I did kind of see bits and pieces to see how she acts. I kind of related everything to that too.
Were you watching her on set? Or were you going back through her filmography?
Lillis: A little bit of both actually. I did go through the movies that she was in. I didn't really get to see a lot but the scenes that I did get to see of her acting, I tried to use that too.
Between playing Camille and Bev, you've been playing characters that are dealing with massive trauma. How do you handle that? Did IT prepare you for Sharp Objects?
Lillis: They do go through this trauma, but the main difference about them is how they react to that. Bev kind of encloses herself in and she doesn't really let anyone in. That's kind of like Camille, but Camille has a more self-destructive kind of personality. Bev gained friends, but Camille was losing everybody. The way she lashed out was very self-inflicted and less on others and more of herself, which is kind of what you had to keep in mind with her character. I have experience with these kind of characters. They are kind of the only roles that I get, but that's good because I have a lot of experience with that. I get to learn different things about the families and how they react and why they react and it keeps you open-minded about this kind of stuff.
When you're playing them, does it get to you personally at all or are you able to detach?
Lillis: I get to detach in a way. In real life I have a very, very supportive, nice family. It is a little especially hard at first to relate to the character, but I always try to find some relation with the character so it's easier for me to kind of be the character even though I have a very, very nice family. So it is a little hard. That's what I mainly try to do. I try to find something about myself as the character and try to be in their shoes and try to find out what would I do and then what would Camille do.
I presume Nancy Drew, who you're playing in a new film, is a little cheerier.
Lillis: Yes, Nancy Drew is definitely not like that, which is good. I enjoy having these characters, but it was kind of a refreshing moment to be Nancy Drew and that was fun. On set people were nice and the role was very sweet and so different.
Jessica Chastain posted an amazing composite of your faces on Instagram. What was coming back to the IT set like?
Lillis: It was really funny meeting the adult versions and looking at the kids and kind of seeing how similar they are which is really fun. In real life, they talk the same way, they act the same way. It was really funny to kind of see both of them together in the same room. I did talk a little with Jessica Chastain. God, she's such a nice person. We talked a little bit about what we thought about the script and what we think about the role and how to portray it. We talked to each other a little bit about that. But, yeah, besides that I always just had dinner with her with the other kids too. It was a fun experience.
Was there anything you noticed specifically about how you and Jessica were alike?
Lillis: She definitely looks a lot like me. But I mostly heard from other people telling me like, "Oh, you have the same mannerisms as her. You kind of have the same tics and the way you speak is kind of similar." I didn't really notice it that much. But after they told me I looked back and I was like, "Oh wait, you're right. She does."
What does it feel like playing the younger versions of these Oscar-nominated actresses?
Lillis: I'm very honored. I'm surprised I got here. I don't know how that happened. I'm very happy that I get to have a chance to work with them to actually be their younger self. It's kind of hard to fathom I get to actually do something like this.