Naomi Watts is worried about re-opening old scars by playing tragic Princess Diana in the upcoming biopic.
"The way she died... is it going to open it all up again?," Watts asked in an interview with Manhattan magazine.
Diana the movie concentrates on the last two years of the princess's life, including love affairs with Dr. Hasnat Khan and Dodi Fayed, as well as the car crash death.
"We're certainly not trying to upset the boys, though they're men now. I hope they're OK with it."
Watts says that taking on the Diana role was the "hardest thing" she's ever done because everyone has a memory of the late and iconic princess.
"It was just really hard to claim her as my own," she said.
"Everybody feels they know her."
Watts also says she was keen to channel Diana - who died in a Paris car crash in 1997 - rather than mimic her, as any attempt to impersonate her speech and physical behaviour would detract from the performance.
"I don't want to get caught up in mimicry - that's the worst thing," said Watts.
"I was to try to embody her and get the essence of her. Those things are really important to me."
Watts also admits she was scared about people comparing her to Diana, who had two sons, Princes William and Harry, with ex-husband Prince Charles.
She said: "I was afraid of the comparison that comes with playing any iconic figure - and because of her memory - we're fond of her memory."
Diana, the movie, is due to open next year.