Kristen Stewart is currently preparing to play Princess Diana in the forthcoming movie Spencer, and it’s already clear that the Happiest Season star is taking her new role very seriously.

During an appearance on Jimmy Kimmel Live!, Stewart opened up about taking on the iconic role. Discussing the royal, the actress said, “It’s hard not to feel protective over her. She was so young … everyone’s perspective is different, and there’s no way to get everything right … what is fact in relation to personal experience.”

Related article: Kristen Stewart Will Portray Princess Diana In Pablo Larraín’s New Drama, Spencer

When Kimmel described Diana as “one of the most beloved figures in the history of the world,” Stewart replied, “I feel sort of the same way about her. It happened really quickly. I didn’t grow up with her maybe in the same way. I was really young when she passed away.”

As for what the new movie will cover, Stewart told Kimmel, “[Spencer] 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.”

Related article: A Timeline Of Princess Diana And Prince Charles’s Whirlwind Romance

Perhaps the funniest moment of the interview was when Kimmel asked Stewart if she would be getting Diana’s haircut, or wearing a wig for the role. “She has very architectural hair,” Stewart explained, “so we’re going to build it … I don’t think I can do it solely with my own hair.”

Spencer is set to start filming in 2021. The film is being directed by Pablo Larraín, who helmed the Jackie O biopic Jackie, with a script from Steven Knight (Peaky Blinders).

This article originally appeared on Harper’s BAZAAR US.