Kristen Stewart on becoming Princess Diana in 'Spencer,' why she decided to share her engagement news

NEW YORK – Kristen Stewart knows she's the last person you might expect to play Princess Diana.

Standing 5-foot-5 and hailing from Southern California, the "Twilight" alum is almost half a foot shorter than the famously statuesque British royal, now the subject of haunting new biopic "Spencer" (in theaters now). So Stewart was surprised when filmmaker Pablo Larraín approached her about the project, which imagines a fraught Christmas holiday with the royal family in 1991.

"(I was) like, 'Dude, no. Trust me, no,' " Stewart jokes, recalling her puzzled first reaction. But after discussing it more, "his assurance was so contagious and (the prospect of playing her) was too sparkly. I was just like, 'Yeah, that sounds so fun.' I'm a human being. I feel protective of this person, but at the same time, I have all the curiosities" everyone else does about the Princess of Wales, who died in a car crash in 1997 when she was just 36.

"Diana was a very mysterious figure, and I felt that Kristen could capture that mystery," says Larraín, who directed Natalie Portman to an Oscar nomination as Jacqueline Kennedy in 2016's "Jackie." "Sure, there was a chance to become similar to Diana physically through makeup and wardrobe. But the most important thing is her magnetism."

Review: Pablo Larrain's brilliant 'Spencer' unleashes a royally wonderful Kristen Stewart

Stewart's transformative turn has been hailed as "brilliant" and "a career best" by critics, and she leads many awards prognosticators' picks in the 2022 Oscar race for best actress. Prepping for the role, Stewart "watched every interview I could get my hands on," studying Diana's breathy timbre and infectious laugh.

"It's hard to laugh or be extremely angry or emotional in a different accent, or impulsively improv something," Stewart says. "But having four or five months to absorb her (through research), I found these things were readily available to me once we started shooting."

Days before its release, Stewart, 31, sat down with USA TODAY to talk about "Spencer" and her recent engagement to longtime girlfriend and screenwriter Dylan Meyer ("Moxie"), which she announced on SiriusXM's "The Howard Stern Show" Tuesday.

What to watch this weekend: Marvel's 'Eternals,' 'Spencer,' Netflix's 'The Harder They Fall'

Question: How do you feel you could understand or relate to Diana?

Kristen Stewart: I always try to live in the moment, in terms of how I interact with cameras that are not movie cameras. I'm so willing to be caught at a wrong angle because that's the only way to really see someone. I feel very much in looking at pictures of Diana that she shares that desire to be honest, even if it's a little floppy and awkward. I sensed a very similar, feral desire to be straight up. I can relate to that desire to connect.

Q: The film depicts how Diana was hounded by paparazzi. Was there a point in your career when you were able to start tuning out or ignoring photographers? Or can it still feel scary and invasive?

Stewart: It’s totally infuriating and inhuman, like we're living in "Men in Black" and they're aliens. But I don't take it home with me anymore. It used to be something that was more emotional, the sort of thievery of it. I'm also not in a place where the bad outweighs the good. I mean, we're sitting here talking about something I love so much.

But walking outside of your house and having people screaming (at you) – I don't think anyone actually considers that while looking at the (paparazzi) pictures. If you were to address that with any normal human, they'd be like, "That's not OK." And yet, I have the same morbid curiosities I shouldn't be concerned about. We're all human, so it's not like I don't get it. It's just annoying.

Q: There's a gorgeous montage in the film of Diana dancing alone in various rooms and outfits. What was your dance experience like before this?

Stewart: I've bopped around a bit. (Laughs.) But (making this movie) opened me up in a really beautiful way. I stood taller in her skin. She has very warm, spiritual energy. In this weird, spooky way – maybe this just exists in my imagination – but I felt her power. It wasn't about being strong: Her power is that she disarms, and I felt disarmed by her. It felt good to be her and dance in her skin.

Q: What kinds of songs did Pablo play as you shot that?

Stewart: It ran the gamut. He would throw on Sinead O'Connor, Miles Davis, Chet Baker. Some of them were sad and contemplative, and some were just wild pop songs. I see the movie and I'm shocked, because I'm like, "I was so happy (shooting that)! I was jumping around listening to the Talking Heads!" But you watch the scene and it's heartbreaking.

Q: How do you feel about the potential that Harry and William could watch this one day?

Stewart: Look, I don't know how much they interact with the stories told about themselves and their family. We really did lead with love on this one. So many people have an opinion about what happened, but we don't. We just really admire this person and were curious what it felt like on the inside. Having gotten to know my version of Diana, I think she believed in art and that multiplicity. I think she'd be stoked we're still talking about her, but we can't know that.

More: Kristen Stewart is engaged to girlfriend Dylan Meyer, shares 'chill' wedding details

Q: Congratulations on your engagement. Why did now feel like the right time to share the news?

Stewart: I've grown to a place where I like to possess details of my life, but also not to the extent that I then can't live. So it's fun and nice to talk about things you're happy about, but to a certain extent. I've always been a very private person, so I think maybe people are surprised that I'm like, "I'm engaged!" But we're stoked. I'm just so lucky and so happy.

Q: What was it like watching "Spencer" with your fiancée for the first time? Do you get self-conscious seeing yourself on screen?

Stewart: My job is so tied to my life. Anyone who says, "Don't take that stuff home with you, don't let it affect your real life" – my real life is so intertwined with what I do as an actor. Also, she's a filmmaker, she's a beautiful writer, and we are collaborators now. So I was just like, "Watch this thing!" I mean, I think I've seen it three times now. I'm not somebody who doesn't watch their work. I literally sat in a screening room with five of my best friends, my producer, Dylan, and was like, "OK, tell me what you think so we can make it better."

Q: "Twilight" has had a recent resurgence on social media, between nostalgic millennials and Gen Zers discovering the series. How does it feel to see it embraced in this new way?

Stewart: It's cool, man. I can't believe we've already cycled through a whole generation. Those movies come on TV and I click through, because I feel like I'm looking at myself in high school. I'm not old enough to not be embarrassed yet, but I love those movies. They affected people in this beautiful way and I'm so glad that's not stopping.

This article originally appeared on USA TODAY: Kristen Stewart felt Princess Diana's 'power' while shooting 'Spencer'