Kristen Stewart as Princess Diana Seen with Onscreen Sons William and Harry

BACKGRID Kristen Stewart as Princess Diana

Kristen Stewart is taking on the role of Princess Diana, the mother.

New photos from the set of the upcoming film Spencer show Stewart as the Princess of Wales with two young actors that appear to be portraying Diana's two sons, Prince William and Prince Harry. The 30-year-old actress nails Princess Diana's casual style, from her oversized blazer to her baseball cap, as she helps the boys out of a car.

The film, which is eyeing a fall 2021 release, is set over the course of a weekend in December 1991, when Princess Diana joins the royal family for Christmas as the Sandringham Estate — and decides to leave her fractured marriage to Prince Charles.

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Jayne Fincher/Princess Diana Archive/Getty Prince William, Princess Diana and Prince Harry

To celebrate the start of principal photography on Pablo Larraín's film, NEON released the first look of their star in full character in January. The Twilight star bears a strong resemblance to the late royal in a red coat, blonde locks and a black hat with delicate netting over her face as she looks off to the side.

"Spencer is a dive inside an emotional imagining of who Diana was at a pivotal turning point in her life," said Stewart. "It is a physical assertion of the sum of her parts, which starts with her given name; Spencer. It is a harrowing effort for her to return to herself, as Diana strives to hold onto what the name Spencer means to her."

During a November appearance on Jimmy Kimmel Live!, Stewart recalled the flowers laid in Princess Diana's honor at Buckingham Palace after she died in 1997.

For more on Kristen Stewarts' new role as Princess Diana in the film Spencer, listen below to the episode of PEOPLE Every Day.

"I was really young, [I] didn't know what was going on," the Twilight actress said. "It's hard not to feel protective of her. She was so young."

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"I mean, everyone's perspective is different and there's no way to get anything right because what is fact in relation to personal experience," she continued.

"My movie takes place over three days, and it's this really poetic internal imagining of what that might have felt like rather than giving new information," Stewart said. "We kind of don't have a mark to hit, we just also love her."

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The actress also opened up about preparing for her highly anticipated portrayal of the late royal, particularly how she plans to nail the "intimidating" accent.

"We don't start shooting until mid-January. The accent is intimidating as all hell because people know that voice, and it's so, so distinct and particular," Stewart told InStyle in an interview released in October. "I'm working on it now and already have my dialect coach."