Just when you think Julianne Moore has done it all, she tackles yet another challenging role. Case in point: playing Carrie White’s hyper-religious, controlling mother Margaret in director Kimberly Peirce’s update of Carrie. Piper Laurie was haunting and horrifying in Brian DePalma’s 1976 adaptation, but while promoting the film at New York Comic Con, Moore revealed hers to be a more fleshed-out version of Mrs. White.

Specifically, Moore went to the source material, Stephen King’s 1974 novel of the same name, to delve into Margaret’s background and infuse dimension into her interpetation. In a roundtable interview, the four-time Oscar nominee discussed Margaret’s madness and updating the role for today’s audiences.

There seems to be a bit of a difference from your Margaret White to Piper Laurie's Margaret White.

[laughs] Maybe not. Who knows?

Well, can you tell us who your Margaret is?

We certainly had a lot to draw on in terms of source material in the book. Stephen King is very, very specific about her and her backstory. The thing that interested me the most about her is … how tremendously isolated she was. She joined this religious sect and then found that they were not strict enough, they were not rigorous enough for her, so she ended up peeling off from them with this man that she met. They had their own church, they would preach to each other. They were so isolated from the community that when she was pregnant she didn't know that she was pregnant – she thought she had cancer, and thought she was dying when she delivered the baby. At that point, her husband had died. So you think like, “Oh, my gosh, here's this woman who has probably had like several psychotic breaks, who is completely socially isolated, who has no one – only had this man who then dies, and is just left with this child.” So you think, this is her only relationship, this is her only community. So I think starting there certainly helped me put into context what she was.

Did you bring some of your fears – as a mother – to your character?

I wouldn't say that. But I do think that I wanted to make sure that I understood that everything that Margaret does to Carrie is out of her desire to parent her correctly. It’s not this sort of random idea of being sort of randomly violent or crazy, because I didn't think that was very interesting. What is interesting is somebody who's so isolated and so concerned with the outside world that she doesn't want her child to have to experience that.

What are some of the challenges of playing a character with such deep psychological issues?

You have to make it entertaining, too! [laughs] You know, part of it is that it's a beloved film, obviously, and novel. It certainly was seminal for me as an adolescent. I still remember huge parts of it, you know, after you've seen hundreds of movies over your lifetime there's so many that you don't remember, and this one I really do. We wanted to make it entertaining, we wanted to make it believable, we wanted to make it scary, we wanted to make it moving – I think we just wanted to give it its justice.

Where do you go to explore this kind of character, aside from the source material? Do you go to other films, experts, books?

No, not really – all I do is read the script. I read the script and I read the book. The book was really most important to me. I can remember I was shooting something in L.A. and they wanted to have a script meeting and they couldn't do it, and so I literally had to go back – and then I underlined everything in yellow so I could have a meeting about the script and talk about everything. And it was so much stuff right there, right away. That's where it comes from for me, always. There have been things where maybe I've looked at film or music but for her it really was about what Stephen King had written.

Is Margaret White the kind of character that you immerse yourself in so much she haunts you after you're finished filming?

No, I was so happy to get rid of her! She's so crazy! Oh, she's so crazy! And she's miserable, too. And Kim kept saying to me, "Isn't there some place where she's happy?" And I'm like, "No, she's not happy!" Because for Margaret, the movie really starts with Carrie – with her period, with rebellion and with her superpower emerging. And for Margaret, there couldn't be anything worse. Because she's had this child, she's taken care of her, she wants her with her – she wants her never to leave, so the minute she starts trying she starts moving away. It's a nightmare. So Margaret is deeply unhappy.

This is obviously going to be a very different movie than the Carrie of 1976. What are some of the things you guys confronted when it came to the subtext of abuse between Carrie and Margaret?

Well this was actually really important to me … that idea that there was ever any abuse outside the house, there are ever any marks on Carrie, I said that can't happen – I don't believe it. I mean, she'd never do that – the child would be taken away from her. And in terms of the violence, too, I said it's sort of random hitting and it doesn't make any sense to me. So, you'll see when you see the movie – I feel like it's integrated in a different kind of way. It's not any nicer, believe me, but there's more intentionality to it. It's not random. It's abusive, but it's not random.

What do you think it is about Stephen King's story that's so timeless?

Did you read his book On Writing, where he talks about where the idea from the story came from, and the girls that he went to high school with? He’s so eloquent about it, and it's really, really touching about how marginalized these girls were – one by their parents religious beliefs, the other one by poverty. How difficult their lives were, how hard it was for them to be accepted in that community, and even later on they both died very young. He took that idea about someone who was so marginalized in society and then put it in a high school and then started it with the whole tampon thing and the incipience of adulthood – I think you're dealing with so many powerful ideas, one of marginalization, another of adolescence and adolescent rebellion and adulthood and tragedy. So I don't know that I could say that it's one thing that he writes about that's made it so powerful, but I do think it's a combination of so many themes.

Does a horror movie demand a particular set of acting skills?

Well, I think from an acting standpoint you never think in terms of genre. There’s a box that your movie's going to be in, but as you're building a character you're not thinking that way. So it doesn't demand a separate set of skills. It maybe demands an outside eye, and certainly from the director. If you have a director who's not acknowledging the genre, then they're going to miss a lot of the fun of the movie, because some of it happens visually, certainly there are scares. We participate in it insomuch as we're working with the director toward it, but you don't think of it when you're building your character.

Carrie opens March 15.