克里斯汀·斯图尔特 扮演戴安娜王妃使她敞开心扉

As a girl growing up on Queen Elizabeth's Sandringham Estate Diana Spencer-whose aristocratic parents shared ties to the monarchy-learned all there is to know about the Christmas traditions of the royal family. Yet by the time she was a royal herself, she struggled to cope with the hectic routine of dinners, small talk and wardrobe changes as her marriage to Prince Charles started to fracture.

"It was purgatory for her," says her bodyguard Ken Wharfe, who joined the Princess of Wales for the holidays at Sandringham in the early 1990s. "She confined herself to spending time in the kitchen with the chef or with people like me, in the hope that time would while away and she could get back to London."

Now the new film Spenser, directed by Pablo Larrain and starring Kristen Stewart as a 30-year-old Diana, examines the princess's private pain during Christmas at Sandringham in 1991. Although the filmmakers spotlight an imagined three days in December-calling the movie "a fable from a true tragedy"-they draw heavily on the real-life circumstances from that time, including Diana's harrowing battles with bulimia and self-harm.

Those who knew her say she kept her struggles under wraps during royal gatherings. "She would have put on a good front for the Queen and the family," says biographer Ingrid Seward, one of the journalists with whom Diana was friendly.

"She was a properly brought-up girl and would have considered it rude to make a scene or a spectacle of herself." She could also be bracingly uninhibited-something Stewart says helped inspire her performance, which is garnering Oscar buzz.

"We kind of danced our way through making Spencer," says the star, 31, who worked with a voice coach to perfect Diana's distinctive speaking style. "Diana herself was really obsessed with movement and dance.

I've always been super intimidated and self-conscious, and just not... it's never been my way into a party. It's never been my way into self-expression at all.

And this movie opened me up in such a cool way."