Kristen Stewart on filming Princess Diana wedding dress scene

Kristen Stewart said wearing a replica of Princess Diana’s wedding gown was a “spooky” experience.

The actor, 31, will portray Diana in the upcoming film “Spencer.” The movie, which takes place over a three-day time period in December 1991, does not reportedly include a full scene showing the wedding of Diana and Prince Charles in 1981. However, Stewart wears the princess’ famed wedding dress in a flashback sequence.

Stewart wears the iconic dress in a flashback montage in “Spencer.”NEON

“When we put that dress on, it is embedded in a montage that kind of flashed her life before you,” Stewart told “Entertainment Tonight” at the Los Angeles premiere of “Spencer” this week. “The wedding dress is embedded in that montage and putting that on was a spooky day.”

Many fans have remarked on Stewart’s uncanny resemblance to Diana in promo pics for the upcoming movie.Neon

A trailer for the film reveals a brief glimpse of Stewart walking outdoors wearing Diana’s iconic bridal gown with flounced sleeves, which was designed by David and Elizabeth Emanuel.

Diana wore the iconic dress in 1981.Getty Images

“We didn’t have to do the wedding scene but I still had one walk, walking outside of this castle,” Stewart said. “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 heart break in a moment.’ I was like, ‘OK got it. Let’s go.’”

Larraín also spoke to ET about Stewart’s emotions while wearing the gown.

“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,” he said.

“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, sharing that while it doesn’t appear in the movie, the dress had a 30-foot train.

Stewart is the latest actor to tackle the role of the People’s Princess. British newcomer Emma Corrin won a Golden Globe for her portrayal of a younger Diana in season four of “The Crown” last year, and Australian actor Elizabeth Debicki is set to play Diana in seasons five and six of the Netflix drama.

In “The Crown,” which portrayed Diana’s wedding in more detail, Corrin wore a near replica of her famed wedding dress. Similar to Stewart, Corrin said the moment she put on the gown was a bit eerie for everyone on set.

“We were filming the scene when you first see her in the wedding dress — I think it was Lancaster House in London — and I had a team of about 10 people helping me put it on, because it’s massive,” Corrin told British Vogue last year. “I walked out and everyone went completely silent. More than anything else I wear in the series, it’s so … It’s her.”