Demi Moore opened up about the intense atmosphere during the filming of Substance, the new horror movie directed by Coralie Fargeat.

The actress, who plays Elizabeth in the upcoming film, revealed in a recent interview with the L.A. Times that she was diagnosed with shingles and had to take a one-week break from filming.

Demi Moore Reveals She Got Shingles and "Lost 20 Pounds" While Filming 'The Substance' https://t.co/Ansku38Cih

— The Hollywood Reporter (@THR) September 4, 2024

“To give you an idea of the intensity, during the first week when I actually had time off, while Margaret was the only one working, I got shingles,” Moore shared. “And then I lost about 9 kilos.”

Her co-star, Margaret Qualley, who plays Sue, also faced her own challenges during production due to the film’s heavy themes. “Oh, yeah, I had crazy acne for a long time,” she added.

However, both leading actresses knew that Fargeat was going to push them to new levels with their roles in Substance, and each fully embraced it.

“You have to leave feeling like you gave it your all,” Moore explained. “It demanded that, and that’s what you want to deliver in something like this.”

The film, a follow-up to the director’s 2017 debut Revenge, follows a forgotten celebrity who decides to use an underground drug—a substance that regenerates cells and temporarily creates a younger, better version of herself.

Watch the trailer for Substance:

“What she does to herself is truly the most violent thing,” Moore commented. “[The script] takes something that is a deeply internalized violence against ourselves and externalizes it in a way that allows the audience to gain some objectivity and then really see what we do to ourselves through this harsh, constant criticism and comparison.”

Fargeat added: “I recently read a slogan in an article about the film that said, ‘Being a woman is physical horror.’ The film can be terrifying on many levels, but the first is about playing with the violence of what we do to our bodies.”