Alicia Silverstone might be best-known for '90s romps like Clueless, Excess Baggage, and Blast from the Past. But the Californian actress who defined the era's idea of cool has been exploring darker realms in cinema, appearing in Yorgos Lanthimos's twisted thriller The Killing of a Sacred Deer; Severin Fiala and Veronika Franz's freaky follow-up to Goodnight Mommy, The Lodge; and now Jennifer Reeder's blood-dripping, coming-of-age monster movie, Perpetrator.

Pulling in polarizing reviews on its film festival run, Perpetrator centers on a teen girl named Jonny (Kiah McKirnan), who on her 18th birthday inherits a strange new power that pushes her to better understand the world around her through truly radical empathy. Silverstone stars as Jonny's hard-as-nails and hot-as-hell mentor, Hildie. Together, they will forge a path of female bonding…while investigating a spade of missing person cases afflicting the local high school.

In a paired interview with Mashable, conducted ahead of the SAG/AFTRA strike, Alicia Silverstone and Jennifer Reeder shared how they came to collaborate, the power of wardrobe, and the secrets of one particularly shocking scene that spurred Silverstone to sign on to the project — though it was later cut from the final film.

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How did Alicia Silverstone get involved in Perpetrator?

NEW YORK, NEW YORK - JUNE 11: (L-R) Christopher Lowell, Kiah McKirnan, Alicia Silverstone, and director Jennifer Reeder attend the "Perpetrator" premiere during the 2023 Tribeca Festival at SVA Theatre on June 11, 2023, in New York City. Credit: Jamie McCarthy/Getty Images for Tribeca Festival

When Silverstone's agent came to her with the offer to play Hildie, Reeder had already earned a reputation as one to watch. Not only had her eerie 2019 horror-musical Knives and Skin won praise from critics, but it also snagged her a spot on Parasite director Bong Joon Ho's 2020 list of 20 filmmakers who would define the coming decade of cinema.

In addition to coming highly recommended, Reeder won Silverstone over with a personal letter that accompanied the Perpetrator script. "I would have said yes to the movie right off of the letter," Silverstone said, "because I just felt such an artist [in the writing]."

"The way she talked, the way she communicated, everything that she said about the character," Silverstone continued, noting that Reeder went into detail about her vision of Hildie's wardrobe. "It was just so exciting to have somebody describe wardrobe to you. I don't think that's ever happened [before]. She just said right away, 'Hildie is wearing tight, tight black skirts, with her hair pulled very tightly back and turtlenecks,' which is not unlike how Jennifer Reeder dresses, by the way. When I first met her I was like, 'Oh, hi, Hildie.'"

At this, Reeder chuckled and concurred, "That's true."

From there, Silverstone read the script and fell in love. "There were so many beautiful moments in the script. One of my favorites didn't make it in the film."

SEE ALSO: 'Perpetrator' review: Alicia Silverstone hits surreal heights in this bloody, feminist horror film

What was the cut scene that made Alicia Silverstone want to make Perpetrator?

Kiah McKirnan splattered in blood in "Perpetrator." Credit: IFC/Shudder

After getting approval from Reeder to spill the details, Silverstone painted the scene.

"Jonny has broken into this house and she's stealing stuff, right?" the actress began. "Now, she hears a person coming into the house. She hides under the bed. And while she's hiding under the bed, this asshole guy comes in with this young girl. And he's trying to have sex with her."

Jonny is hidden under the bed, a silent witness. "They're fucking and on the floor. He wants to do it on the floor because he doesn't want his wife to find out by, like, messing up the bed," Silverstone explained. "So, he's on the floor fucking her. And the girl underneath the bed looks at Jonny, and Jonny looks back at her, and they say to each other, they mouth, 'Are you okay?' And this made me just go: What is this womanness? That they both checked in on each other? Are you okay? That happening? Just what an incredible insight and feeling about these women, and so unusual. Often, we are pitted against each other [in movies]; it's not that, and that was just such a loving, beautiful moment."

"We shot that scene," Reeder noted. "We cut it just for pace. But I stand by that scene. I'm recycling it for something else. Another thing."

Still, Silverstone feels the message of this scene survives in Perpetrator, even with it being cut out. "It's still there," she said. "It's throughout the whole thing. That was just really the moment that made me feel like I get where she is, because [Reeder] loves blood, and she loves girls. And that's in all of her movies."

"That's true," Reeder replied.

What was in the letter Jennifer Reeder sent Alicia Silverstone?

Jennifer Reeder, director of "Perpetrator." Credit: Shudder/IFC

The filmmaker felt it was important to introduce herself and her idea. "I didn't want the script to be a surprise," Reeder explained. Having seen Silverstone in such daring thrillers as The Killing of a Sacred Deer and The Lodge, "I knew that you were game to do some gnarly stuff," she said to Silverstone. Still, the actress beloved for her "blonde and breezy" persona was being asked to do something very different for the savage and stern Hildie.

Reeder drew a comparison between her movie's matriarch and the vampire queen Catherine Deneuve played in The Hunger, Miriam Blaylock. "That reference was so everything," Silverstone said of the moody 1983 film, which co-starred Susan Sarandon and David Bowie. "That's why I wanted to play Hildie. But I just thought, what an exciting role, and the fact that there was a clear reference of sort of this matriarch. Catherine Deneuve carried herself in this very elegant, graceful [way and was] quiet in the way she spoke."

Silverstone drew inspiration from Deneuve's performance but made clear she didn't set out to mimic the French actress. "[I wanted to] give a sense of what she was doing, the essence of it," she explained, "and bring it to this matriarch who's trying to take care of this young girl and is perceived as a witch or a monster, but really is very loving... She wants everybody to get their shit together and come into their power and be their fierce, beautiful selves."

Beyond a description of Hilde's look and her Hunger vibe, Reeder wrote to express to Silverstone why she was perfect for the role. "Not just saying kind of, like, 'Because you're iconic,' which is true," Reeder said.

"Even when we were casting for Knives and Skin, I was really interested in Alicia," Reeder revealed. "Certainly knowing that she could carry any role" — at this point she spoke to Silverstone directly — "because you're truly a brilliant actor. But I love that you take chances. I think that makes a big difference. But it also made the most sense for Hildie, who is this matriarch of really powerful women, and especially a woman who's guiding this teenager through this transition, that your own sort of, like, meta-story involves being introduced to the world as a teenager, and then being able to evolve in front of us. I mean, I feel like you really are so iconic that there are people [who] have never met you [but] you are such an important part of their life. I know that directly, having people just message me all the time. They're kind of like, 'Tell her I love her.' And I'm like, 'Maybe, if she's behaving that day.'" Silverstone laughed. "That was not lost on me," Reeder continued, "your professional provenance."

"But, I mean, like, woman-to-woman, person-to-person, artist-to-artist," Reeder explained, "I've got the ability to be as articulate as I want, and you might have just one shot to get somebody to say, like, 'I'll read this girl's script.' Something like that matters.

"I'm a woman who deeply values my friendships with other women," Reeder continued, recapping the letter's secrets. "And so, I don't want this to be a one-off, like, I want to be your friend. And I want you to trust me when you get on set. And it starts with just writing something that feels like it's totally coming from my heart, because then you read the script, and it is kind of gnarly. But I wanted Alicia to know from the tone of that letter that I was a caring, smart filmmaker, who, if she said yes to coming on this journey with me, she wouldn't regret it."

Perpetrator debuts in select theaters and on Shudder Sept. 1.