Naomi Watts, who is set to play Princess Diana in the upcoming biopic Diana, has said she was very nervous about getting the "distinct voice" right.
Watts, 44, said: "I was very nervous about the accent. She had a very distinct voice - she came from aristocracy so she was quite posh, but there was a warmth there, too. Her accent wasn't too 'fruity'.
Speaking to Total Film magazine, she said: "She also had this thing where the bottom half of her face didn't move that much."
The film focuses on the two years before Diana's death in 1997. In one pivotal scene, Watts recreates Diana's interview with the BBC's Panorama show, in which she said there were "three of us" in her marriage to Prince Charles.
The actress revealed that she studied the interview every day in order to get it "exactly right".
She added: "I watched it pretty much every day during make-up; I went running with it playing in my iPod.
"It was probably the thing I was most committed to getting exactly right - the head moves, the eye moves, the hair - because everyone knows it so well. It's such an extraordinary piece of TV."
