Demi Moore admits shooting The Substance's nude scenes was 'vulnerable experience'

Demi Moore has admitted it was "a very vulnerable experience" filming full-frontal nude scenes for the body horror The Substance.

In the shocking new film, the G.I. Jane star plays a fading Hollywood actress who takes a black market drug called The Substance and spawns a younger version of herself played by Margaret Qualley.

According to reports, Moore, 61, spends time studying her nude body before deciding to take the drug, while both she and Qualley engage in a fight while completely naked.

During a press conference at the Cannes Film Festival on Monday, Moore reflected on baring it all on camera.

"Going into it, it was really spelled out - the level of vulnerability and rawness that was really required to tell the story," Moore said, according to Variety. "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."

She added that the explicit scenes "pushed (her) out of the comfort zone" but she knew they were "necessary to tell this story".

The Striptease actress also heaped praise on her co-star Qualley, 29, for making her feel safe.

"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 explained.

The gory horror received a rave reception at its world premiere on Sunday, with it reportedly scoring the longest standing ovation of the festival so far.

Qualley, who attended the premiere, was absent from the press conference as she needed to get back to the set of her next movie.