Raffey Cassidy’s entrée into the acting world was a complete accident—and not particularly auspicious. At the age of seven, she was waiting for one of her elder brothers, who at the time was an aspiring actor, outside of an audition for a BBC drama when the casting director, in need of a young girl for a small role, spotted her and asked if she’d like to give it a try. “I don’t remember much other than sitting under a table hacking away,” says Cassidy, now 16 and a high school student in her native Manchester, England. “It was a little coughing and dying part. But I loved being on set immediately—mostly the costumes and the makeup at the time. And I’ve been working ever since.”

And working with some of Hollywood’s biggest names, no less. Her breakthrough, in 2015’s sci-fi adventure flick Tomorrowland—in which she played an animatronic girl—had her sharing the screen with George Clooney. In 2017, she was Nicole Kidman and Colin Farrell’s troubled teen daughter in Yorgos Lanthimos’s eerie thriller The Killing of a Sacred Deer, which won Best Screenplay at the Cannes Film Festival. And most recently, she played both a young Natalie Portman and Portman’s daughter in Vox Lux, which centers on a school shooting survivor who, after singing at a memorial, becomes a hugely successful—though deeply damaged—pop star. “It’s definitely the dark side of fame. She never really deals with the aftermath of the trauma so it’s all coming back when she’s older,” says Cassidy of Celeste, the role she shares with Portman.

And share it they actually do. This isn’t the sort of younger-self role that’s relegated to a few flashback scenes. Cassidy helms the first hour of the movie solo and, once Portman appears on the screen, the willowy Brit—who slips seamlessly into the role of Albertine, Celeste’s introverted teen daughter—more than holds her own. As the Washington Post review of the film said —in the headline, no less—“Natalie Portman gets top billing but is upstaged by an actress you’ve never heard of.”

Raffey Cassidy wears a Simone Rocha blouse and headband; Miu Miu headband.

Photograph by Jeff Henrikson; Styled by Emma Wyman. Hair by Dylan Chavles for Oribe at Art Department; Makeup by John McKay for Koh Gen Do at Frank Reps; Manicure by Mimi D at Celestine agency; Producer: Claire Donoghue; Photography Assistants: James Bailey, Jeremy Jackson; Fashion Assistant: Marcus Cuffie; Production Assistant: Brendon Schaufert.

Inhabiting two different but not entirely separate characters was, in Cassidy’s words, “hard to get your head around.” But that challenge, she says, is what drew her to the role, as did the opportunity to watch one of her screen idols in action. “I’ve always really admired Natalie so it was fun to see how she works and the way she behaves on set—professional but also having fun at the same time, which I think is always important. You’ve got to enjoy what you do.”

Which is why she’d like to try her hand at lighter fare—“I’d love to do a comedy, after all that darkness” she says—and also devote some time to the passions that got her hooked on moviemaking in the first place: makeup and costumes. After an unofficial apprenticeship with makeup artist Monica Huppert while making Tomorrowland, she now practices on her sister and three brothers, tricking them out with gory wounds and various disguises. “They love a fake mustache,” says Cassidy. And, after making her own clothes for years, she’s now planning on applying to design school. “I want to do acting forever and ever but I would also like to do something involved with fashion,” says Cassidy, who recently got a behind-the-scenes glimpse of the pret-a-porter magic as an ambassador for Miu Miu and a star of the label’s AW18 ad campaign. “Central St. Martins would be a dream,” she sighs. “I’m aiming high!“