In The Substance, Qualley takes on the role of Sue, a more youthful clone of Moore's aging actress who is created by an illicit serum. The film features nudity and plenty of hard to watch moments as the two women, who share one consciousness, inject themselves with the film's titular serum.

Demi Moore, Margaret Qualley, Dennis Quaid and more stars hit the red carpet for the L.A. premiere of their film, 'The Substance.' See all the photos.

Finally, “The Substance” is very much a woman’s movie. The way writer-director Coralie Fargeat presents Demi Moore and Margaret Qualley — the matter-of-fact way in which she films their bodies, and the trust that she elicits from them — has the unmistakable stamp of a woman director. This is obvious within minutes.

From daunting high-energy choreography to nine-hour prosthetic application, the stars tell EW "The Substance" was a satisfyingly grueling, months-long shoot.