The film is set over a three-day period during Christmas in the early 1990s, where Diana is spending time at the royal family's Sandringham estate. It takes a strikingly different perspective to that of The Crown, the hit Netflix series which saw British actor Emma Corrin play Diana during her early years through to her wedding and complicated marriage to Prince Charles.
Instead, Spencer digs deeper into Diana's isolated, paranoid perspective—even featuring troubling scenes of her self-harming and struggling with bulimia.
“She was really honest about her relationship with her body and food,” says Stewart.
“And this feeling that she wanted to disappear, that she was just diminishing, that she was wasting away, it became so physical for her. To live inside a female body, an unacknowledged, muzzled female body, is a violent experience and it is not easy to talk about. It’s a complicated matter, obviously. But she was really vocal about it. And so we had to go there.”
Making a film where her character connects to the ghost of Anne Boleyn—the beheaded second wife of King Henry VIII – Stewart admits she sensed Diana’s presence at times.
"I wasn’t like, ‘Ooh, spooky. She’s here!’ But I was just like, ‘Maybe.’ To play her, to deeply consider her and represent the idea of her, felt so good. Even at her lowest moments, the preservation of that pervasive love felt beautiful. It became physical for me, and that in itself felt spiritual."
Stewart’s own intense experiences certainly lean into Spencer—and Diana's own lived reality. It’s hard not to recall Stewart grimacing through red-carpet duties during Twilight mania, or at the paparazzi hordes tailing her and co-star Robert Pattinson during their on-off, four-year coupling.
So how did she cope? “I was fine,” she says matter-of- factly. “I grew up. I work on movies and in between I talk about them with people.”
It begs the question: How important was it that she didn’t hide away or become reclusive?
“Yeah ... I absolutely love people,” she replies.
“I want to make movies about us. I mean, I’m an actor. I know that I might not seem like the most performative person but, at the same time, the feeling of being seen and revealed and having the power to do so is a really beautiful position. It’s a nice life. So no, I didn’t really have to run from anything.”
For the full cover story, pick up the February issue of marie claire Australia, on sale Thursday January 13.