Kristen Stewart is doing everything in her power to embody the grace and style of late Princess Diana in her much-anticipated upcoming movie, “Spencer.” In order to achieve that level of perfection, the 31-year-old actress had to put on a replica of Diana’s wedding dress, and she says it was a “spooky” moment for her. Stewart opened up about her experience in an interview with ET.

"When we put that dress on, it is embedded in a montage that kind of flashed her life before you. Even though the movie takes place over a three-day period and even though I play her as a speculatively 29, 30-year-old person, we still wanted to give a taste of the scope of her life," Stewart shared with ET at the Los Angeles premiere on Tuesday. "Kind of touch on every part, even if it was in kind of lyrical dance. And the wedding dress is embedded in that montage and putting that on was a spooky day."

"We didn't have to do the wedding scene but I still had one walk, walking outside of this castle," the 31-year-old actress recalled. "I was like, 'Wait, but this is so particular.' This actually does land on a very precise day of her life and [the director Pablo Larraín] was like, 'Take everything you learned about that day, all of your emotional responses that you have accumulated, put them all right here. What does it feel like to believe in an ideal that then becomes very, very apparently farcical? It's kind of just like, let your heartbreak in a moment.' I was like, 'OK got it. Let's go."

Talking further about filming Diana's wedding day, director Larrain told ET, "It was very iconic, I think Jackie Duran and her team, our costume designer, worked really hard on it and it's obviously a very particular dress that we all remember."

Larrain further continued, "I think when [Kristen] wore it, she was, she had mixed feelings. She was scared and excited, which also worked for the character as we were shooting. We got to that, I think that's exactly what's in the movie."

"It wasn't fear, it was the challenge of wearing that dress, taking that on and it was hard to walk with it. It was a big structure," he added. "It's not in the movie, but the train had 30 feet, maybe more," the director concluded.

“Spencer” is set in December 1991, and the movie focuses on three specific days of the controversial and tragic life of the People's Princess, as she faces the end of her marriage to Prince Charles while spending Christmas at Queen Elizabeth’s Sandringham Estate in the 1990s. The movie is slated to release in theatres on Nov. 5.

Kristen Stewart
VENICE, ITALY - SEPTEMBER 03: Kristen Stewart attends the red carpet of the movie "Spencer" during the 78th Venice International Film Festival on September 03, 2021 in Venice, Italy. Stephane Cardinale - Corbis/Corbis via Getty Images