Margaret Qualley Is Getting the Hang of Being a Movie Star

Margaret Qualley could finally breathe again.

“I’ve been working a lot,” she said over iced tea at Clark’s, a Brooklyn Heights diner near where she lives with her husband, the music producer Jack Antonoff. “I’m relishing these little lull moments.”

Qualley, 29, has more than earned a break. After making a striking debut 10 years ago in the HBO series “The Leftovers,” she appeared in “Once Upon a Time … in Hollywood,” followed by Emmy-nominated performances in “Fosse/Verdon” and the Netflix mini-series “Maid.” In the past year, she starred in “Poor Things,” “Drive-Away Dolls” and “Kinds of Kindness,” and when we met, she had just returned from shooting three back-to-back movies — Ethan Coen and Tricia Cooke’s “Honey Don’t!,” John Patton Ford’s “Huntington” and Richard Linklater’s “Blue Moon.”

Moviegoers will next see her in “The Substance,” a film that is somehow a departure from all of the above and one she acknowledged was uniquely challenging. Directed by Coralie Fargeat and slated for release on Sept. 20, it is a body-horror blood bath in which Demi Moore plays Elisabeth Sparkle, an actress who, attempting to recapture her fading youth, injects herself with a mysterious serum.

The result is Sue, played by Qualley, a younger, taller, “perfect” woman who emerges fully formed from Elisabeth’s body. The two of them must trade places every week, with the one who’s off-duty kept nourished by IV bags of potions. But soon enough, Sue develops a taste for her brand-new world and doesn’t want to be put on ice when it’s her turn to hibernate.

Qualley was in Panama, shooting Claire Denis’s “Stars at Noon,” when she read the script, and was drawn to the prospect of playing a character who seemed “really far from me,” she said.