Hugh Grant gets top billing as Heretic‘s biggest star, but Chloe East and Sophie Thatcher are the heart and soul of the film.

In Scott Beck and Bryan Woods’ new religious horror film, East (The Fabelmans) and Thatcher (Yellowjackets) play Sister Paxton and Sister Barnes, a pair of Mormon missionaries deployed to Mr. Reed’s (Grant) mysterious Colorado compound. As they begin to discuss their faith with the disarmingly charming homeowner, Grant’s character gradually becomes more hostile to the concept of organized religion, prompting Barnes to question her beliefs and Paxton to become more resolute in hers.

The two actresses both grew up in the Church of Jesus Christ of Latter-day Saints (popularly known as LDS or Mormonism) – although the directors did not know the actresses’ backgrounds when they auditioned.

“They were raised Mormon, and that wasn’t necessarily on our bingo card when we were casting,” Beck says Entertainment weekly. “We weren’t like, ‘We need to find two actresses who were raised Mormon.’ But the reason they won the role is because they were so truthful when they played it. We kept going back to our casting director and asking, ‘Are there more people like these two? Because there’s some truth in that.’

He continues, “We didn’t know they were raised Mormon. We could just feel it; we could feel it. We heard it in their voices and the approach. And I think the way they played the characters, they gave them the utmost respect because they have Mormon families. And so they share the empathy and love that we also share for those characters.

Thatcher and East both tell EW that they immediately felt an innate understanding of Sister Barnes and Sister Paxton — and that they both selected outfits they knew young Mormon missionaries would choose during their self-tape auditions. “We did chemistry readings with different girls, but I had heard from our casting director that Chloe had grown up Mormon and had a Mormon family, so there was an instant connection,” Thatcher says. “We’ve found a lot of parallels in our lives and are connected, and I think they’ve seen that and seen the truth behind our connection to the religion.”

East says her religious upbringing informed her work every second Heretic. “It was everything for my performance,” she says. “A lot of the choices I made and the little quirks were all things I learned from going to church.” The actress makes it clear that she wasn’t as persistent an evangelist as her character: “Growing up, I was never the one telling my classmates about the church and why they should join it. I never went on missions or anything like that. ”

But Paxton’s character still seemed almost disturbingly familiar to the actress. “I just felt like I knew this character in my bones,” she says. “I wish I didn’t know so well and I had to research things, but I was like, ‘I get it.’ Unfortunately, I was this person or I have this person in me that I can use in this film. But it’s very nice to have a role that comes somewhat naturally.

Thatcher had a similar experience. “It felt much more personal than other projects,” she explains. “It felt like I was tapping into something I knew a while ago, but it was easier to tap into because all I was thinking about was myself when I was younger: how I held myself, how I presented myself, and just thinking about my family and my thoughts, specific ways and how they talk, how they present themselves. I just had my mother’s side of the family in mind.

East believes Heretic gives a more nuanced picture of her family’s faith. “You always see very extreme shots – The Book of Mormon musically and even Under the banner of heaven is a very specific kind of extreme Mormon mentality and extreme,” she says. “I know a lot of Mormon friends who watch that show and say, ‘That’s not who we are. That’s weird. That’s not us.’ And then you have a truer, more current, more modern version of Mormonism that many of my friends identify with. And you just don’t see that very often. You don’t see this version of Mormonism played out.”

Childhood friends Beck and Woods come from different religious backgrounds. “I was raised Presbyterian, went to church every Sunday and did vacation Bible school. Church and religion were really my formative years,” Beck explains. “And when I was in high school, I met my girlfriend, now wife, and she’s Jewish and came from a Jewish family. And when we got married, it was just like this combination of religious backgrounds.”

Woods, on the other hand, married into a Mormon family. “I wasn’t raised Mormon,” he clarifies. “The Mormons’ idea was, ‘Who are these people? What is this?’ I didn’t really know much about it until I met my wife. And then we have a billion Mormon friends. But all our friends and family are all of a different faith. We have a lot of atheist friends.

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These connections with friends and family from different faiths ensure that the filmmakers have a strong feeling for their main characters: they see themselves and their loved ones in the core trio of the film. “We have so much love and empathy for these two women,” Woods said. “The movie is very personal, so all the characters feel like they’re all kind of in between them. Mr. Reed and the sisters — they all feel like people we know and love.”

The filmmakers took special care to take the characters’ faith seriously. “It’s so easy in the media, especially among Mormons, to paint a comical picture because there is naivety and there are just elements that are inherent to Mormon culture that can be comical to outside eyes ” says Woods. “We don’t necessarily shy away from that because I came into a Mormon family and there were things that were amusing to me as an outsider, and so we pushed those buttons. But the deeper we got into the Mormon family, culture, the more clear it became that there is an intelligence and a warmth and a sincerity and all these beautiful things that we really respected.”

Heretic now playing in theaters.

These interviews have been edited for clarity and length.