"I'm working on it now and already have my dialect coach," the actress said
Kristen-Stewart, Princess-Diana
Kristen Stewart; Princess Diana
| Credit: Kimberly White/Getty Images; Tim Graham Photo Library via Getty Images

Kristen Stewart is feeling the pressure when it comes to her upcoming role as Princess Diana in Pablo Larraín's drama, Spencer.

In a new interview for InStylethe 30-year-old actress opened up about how she's 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 said. "I'm working on it now and already have my dialect coach."

The Twilight star said she's also read several books about Princess Diana to help her embody the late icon.

"In terms of research, I've gotten through two and a half biographies, and I'm finishing all the material before I actually go make the movie," Stewart said.

"It's one of the saddest stories to exist ever, and I don't want to just play Diana — I want to know her implicitly," she added. "I haven't been this excited about playing a part, by the way, in so long."

kristen Stewart
Kristen Stewart
| Credit: Axelle/Bauer-Griffin/FilmMagic

The film is expected to take place over three days as Princess Diana, who died in a Paris car crash in 1997, realizes she needs to end her marriage to Prince Charles while spending Christmas at Queen Elizabeth's Sandringham estate in the 1990s.

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When announcing that Stewart was cast in the coveted role back in June, Larraín told Deadline that she was "one of the great actors around today."

"To do this well, you need something very important in film, which is mystery," the filmmaker behind Jackie said at the time. "Kristin can be many things, and she can be very mysterious and very fragile an ultimately very strong as well, which is what we need. The combination of those elements made me think of her."

"The way she responded to the script and how she is approaching the character, it's very beautiful to see," he added. "I think she's going to do something stunning and intriguing at the same time. She is this force of nature."

Larraín also said that Stewart's "diverse" resume of films is what drew him to choose her for the part.

"I've seen movies from Kristin that are so diverse it's incredible, showing different layers and her diversity and strength as an actress," he said. "We're very happy to have her, she's very committed. As a filmmaker, when you have someone who can hold such a weight, dramatic and narrative weight just with her eyes, then you have the strong lead who can deliver what we are looking for."