Demi Moore’s new film, the feminist body horror “The Substance,” sees her bare it all, with several scenes featuring full nudity. At the Cannes Film Festival press conference for the film on Monday, the 61-year-old actor discussed the “vulnerable experience.”

“Going into it, it was really spelled out — the level of vulnerability and rawness that was really required to tell the story,” Moore said. “And it was a very vulnerable experience and just required a lot of sensitivity and a lot of conversation about what we were trying to accomplish.”

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In the film from “Revenge” helmer Coralie Fargeat, Moore plays a fading celebrity who uses a black market drug the film is named for — a cell-replicating device that winds up creating a young, better version of herself (Margaret Qualley). Not only must she share a space with this new creature, she has to spend half her time in a dormant state so the other can thrive. In an early scene when Qualley is “birthed” so to speak, Moore spends a long time studying her nude body before pulling the trigger on the drug. When Qualley emerges, she too marvels at her supple new skin suit. It’s a stark but perhaps necessary display of full-frontal for both.

Moore also credited Qualley — who was not on hand for the press conference because she had to travel to a shoot — with making her feel comfortable on set.

“I had someone who was a great partner who I felt very safe with. We obviously were quite close — naked — and we also got a lot of levity in those moments at how absurd those certain situations were,” she said. “But ultimately. it’s just about really directing your communication and mutual trust.”

As the film progresses, Moore becomes horribly disfigured thanks to the abuse her other half Qualley is inflicting on her. By the film’s last act, she quite resembles Anjelica Huston from the 1990 film “The Witches,” after she transforms into a humpback abomination.

“It was very strange,” Moore said of seeing herself in the prosthetics both on set and at the premiere screening on Monday. One thing that helped was “my dog still recognized me. It was my touchstone of reality,” she said. The pooch in question is Pilaf, a purse dog who has stolen hearts around the world in recent weeks, sitting front row with Moore at the Gucci cruise collection runway show and posing for photos on the Croisette in recent days.

Dennis Quaid also stars in the film as an “asshole,” as he described his character during the presser. The late Ray Liotta was meant to have the role before his passing in May 2022, and Quaid dedicated his performance to him.

“In my heart, I dedicated this role to Ray Liotta, who was set to play it,” Quaid said. “It was this week, two years ago that he passed, so I’d like to remember him. He was such an incredible actor.”

Cannes went wild for “The Substance” at its premiere on Sunday night, giving the film an 11-minute standing ovation, the longest of the fest so far.

In an interview with Variety, the French director discussed the film’s feminist themes, saying that body horror is “the perfect vehicle to express the violence all these women’s issues are about.”

With an undercurrent of #MeToo at this year’s festival as the movement grows in France, Fargeat hopes the film will shine even more light on the issue. “It’s a little stone in the huge wall we still have to build regarding this issue, and to be honest, I hope my film will also be one of the stones of that wall. That’s really what I intended to do with it.”

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