A day before the world's most photographed woman is reincarnated again in the world premiere of a Hollywood film, the actress who reinterprets her last two years for the silver screen is full of trepidation.
"Of course, I'm nervous. I'm nervous as I always am when we come to a point when the film is being viewed by the audience," Naomi Watts says.
She was speaking to the press in a hotel in London to promote Diana, which opens in Singapore tomorrow.
"In this case, it's much more nerve-racking because everybody walks in there knowing who she is."
In a little black number that accentuates the actress' bird-like features more than her curves, one would imagine conquering the red carpet to be little more than a matter of professional equanimity for the British-born, US-based artist, acclaimed for her roles in Mulholland Drive (2001), 21 Grams (2003) and The Impossible (2012).
After all, she has had to live through similar moments in real life as a celebrity, and on screen as the late Princess Diana, self-appointed "Queen of People's Hearts".
Watts, 45, admits that she took a while to agree to the role, conceptualised by screenwriter Stephen Jeffreys in a movie directed by Oliver Hirschbiegel (Downfall, 2004). Since its release in the United Kingdom in September, the film has been slammed by the British press for over-sentimentalism.
In an interview prior to its debut, Watts herself was all-a-jitter and defensive of her choice.
"I wrestled with the decision in the beginning. How do you take possession of a character that everyone feels they know so well?" she asks.
"But what made me say 'No' was also what made me say 'Yes' in the end. It also intrigued me, that challenge. Taking that kind of transformation physically was an interesting idea."
Indeed. For many audiences, one of the movie's most titillating draws would be measuring Watts up - and her make-up and fashion team - exactly against the much-filmed and written-about Diana.
No surprise, then, that the actress admits to becoming nothing short of "obsessive" about her target. She read every book, article and letter she could lay her hands on.
She had Diana's historic Panorama interview with Martin Bashir on her iPod on repeated play while running in the park and driving around town. She froze part of her face to capture the late princess' unique facial gestures and mannerisms.
On occasion, filming was surreal - not least when Watts had to wear Diana's clothes.
"The pale blue dress; that one by Azagury. According to the designer that was the actual dress that she wore," she says.
"It fit me. It was eerie. I was quite impressed and surprised by how short it was."
Watts says she tried to get under the skin of the late mother of the future king of England, tapping into her alleged insecurities, her well-documented need for love and approbation, her up-and-down relationship with the paparazzi whose antics eventually led to the notorious car crash in a Paris tunnel in 1997. She and her lover Dodi Al-Fayed were killed.
"I was impressed by her level of empathy and her intelligence and her sense of humour, her rebellious streak, the kind we all always wish to have," Watts says.
"And when the press is ruling your life and has that much power over you, I imagine that there would be a desire and a need to control it as much as you could."
In the movie, Diana is shown manipulating journalists into taking now- infamous shots on a luxury boat with Al-Fayed as part of a larger, private plan to make her real paramour, heart surgeon Hasnat Khan (Naveen Andrews), jealous.
It is the princess' less-documented relationship with Dr Khan, now a divorced practitioner teaching at Basildon University, that takes on the emotional heart of the film.
As director Hirschbiegel says, scenes of the two courting, including Diana sneaking out in a wig to renowned London jazz bar Ronnie Scott's, and her stashing of Dr Khan in a car boot, were "well-documented events".
"Even her baked beans and toast; she really liked to make her cucumber sandwiches. It calmed her mind," he says.
"Also with cleaning - she would clean for hours. She would clean the palace. She would wear these rubber gloves, it would calm her down, give her a sense of normality."
Normality or no, the real Khan himself was not impressed, damning the movie trailer in comments to reporters, saying that what he had seen so far was based on "cruel lies".
Hirschbiegel shrugs. "I like the Hasnat Khan that we created," he says.
"He's an unusual example of an old-fashioned gentleman. He's a true man, who has devotion and the calling to be a doctor, but at the same time, has a smart sense of humour," he adds.
"I wouldn't want to be in this position, to have someone make a film of my life. But what can you do? It's a known story. It's just a matter of time before it would happen."
Watts herself says she "can only hope that people feel we've told her story in a delicate and respectful way".
But Khan himself was not the only obstacle to the making of the film. Hirschbiegel adds that his own sense of political correctness prevented him from creating extended scenes involving Charles, or Diana's two children.
Indeed - one might even go so far as to say his restraint has lent the movie the air of a hagiography. "In the original draft, they had a couple of scenes, but the more I got into it, the more it didn't feel right to have them in there. It would have become speculating and sensational."
Ironically, he relates, it was Buckingham Palace which had provided some help in the end, allowing the crew to film outside Kensington Palace and Kensington Gardens.
The movie opens at an interesting time for the Royal family, when new conspiracies in the press have surfaced over Diana's death and possible Special Air Services' involvement.
What does Watts think?
"It's not for me to comment other than say that it's a testament to who she was and how great she was that we're clearly still very uncomfortable with her death."
She prefers to respond to happier press obsessions of late, referring to news of the birth of Kate Middleton and Prince William's Baby George with a cheeky riposte:
"Wow - I'm a granny now!"
Diana opens tomorrow
Get a copy of The Straits Times or go to straitstimes.com for more stories.