Demi Moore's new film, The Substance, begins normally enough. Set in Los Angeles, it opens with an aerial view of the Hollywood Walk of Fame, where a new star is being installed. Builders are seen taking great care as they lay it, and there is great fanfare when it opens to the public.
But over time, the star honouring Moore's character Elisabeth Sparkle becomes cracked and damaged. It gets trampled on and ignored. One passing man drops his burger, leaving it smeared with ketchup.
The whole sequence lasts only a minute or two, and although the metaphor is unsubtle, it perfectly sets the tone for the film that follows; its themes of youth, beauty and relevance, and how far people will go to achieve them. Then the movie takes a very dark turn. Fired from a TV show due to falling ratings, Sparkle goes to extreme lengths to create a perfect version of herself.
The Substance ultimately becomes a straight-up body horror, packed full of blood and gore, which has prompted both controversy and acclaim. "It was a completely unique, out-of-the-box script, you could tell it was visually stimulating," Moore tells BBC News, "and at the same time, we had no idea how it would end up, which made it even more risky and juicy." The role required the 61-year-old to embrace being unglamorous, to put it mildly, highlighting her ageing character's own fading beauty.
"I felt like that was why I wanted to do it, in a way," Moore reflects. "Part of what made it interesting was going to such a raw, vul.