Demi MOORE

The Substance star has reached a State of enlightenment.

Jacket, $7,000, shorts, $5,500, GUCCI. Earrings, bracelet, HARRY WINSTON. Pumps, GIUSEPPE ZANOTTI, $995.

PARTWAY THROUGH The Substance, a body horror film from French writer and director Coralie Fargeat, there's a brightly lit, low-angle close-up on Demi Moore's bare butt. "It's like, ugh," Moore moans, "it bugs the shit out of me." She could have asked for it to be edited, but as much as she dislikes it-and really, show me a woman who would enjoy seeing such a shot of her derrière on the big screen-"I didn't ask for any adjustments because I knew it was in service of something that was more important than me," Moore says. "It felt like any hardship, any exposure of my own insecurities, would be worth it if I was part of bringing forward the conversation."

In The Substance, Moore plays Elisabeth Sparkle, an actress-turned-TV fitness instructor, who is fired from her show on her 50th birthday and resorts to taking a neon substance that turns her into a twentysomething version of herself (played by Margaret Qualley), eventually with monstrous results. Moore knew that the role, with its full-body nudity and purposefully unflattering lighting, would challenge her-and that's exactly what she wanted. "There was an incredibly liberating aspect to stepping into this really vulnerable, exposed place emotionally and physically," Moore tells me, her micro Chihuahua, Pilaf, napping peacefully beside her on a sofa in her L.A. living room. "The film gave me the opportunity to look at where my ego was kind of running the show, where I was giving up my power, and it pushed me to find a little bit more gentility and acceptance of myself as I am."