Emma Corrin was on a train in early 2019 when she received the call that would change her life.
It was her agent. "She's normally very together and calm," notes Emma, only here "she sounded really weird".
Evidently The Crown had called and asked if Emma could stand in to play Diana in the read-through for the auditions for Camilla.
This was not an audition at all, they stressed, and Emma would be paid for her time; it was merely a request for help.
But both Emma and her agent spied an opportunity. "It was worth giving it a good shot," says Emma, who had just graduated from Cambridge University.
She immediately embarked on background research and got to work on Diana's "distinctive voice".
Although she hadn't formally trained at drama school, Emma had acted since primary school and at university, alongside her academic studies, she played Juliet in a Shakespearean production that toured Japan.
Twenty-four-year-old Emma was a baby when Diana died but she had always played a part in her life.
"I don't have any living memory of her, but I had a huge awareness of her before I was cast in The Crown and those feelings are mainly ones of appreciation and love," she says.
"I saw her as this person who broke the mould. I was very inspired by the empathy that she displayed and her incredibly warm and generous spirit."
"It was unlike anything we'd seen in a person in the royal family and I think I grew up in awe of her strength."
Another reason for Diana's special place in Emma's upbringing is that both she and her mother – Dr Juliette Corrin – bear an uncanny resemblance to the late princess.
"My mum's very fond of Diana, always has been and because she looks so similar to her it's something that has always been commented upon in her life and then throughout mine when I was at school," Emma explains.
"I'm very close to my mum and I guess Diana's become something that we've shared together – an interest in her and a fondness for her."
That first read-through led to another and another, and in the nine months that followed, Emma was thrilled when she was called in to properly audition for the role.
"Mum's a speech therapist and we used to go to cafes together and run the lines and practise the voice and talk about it. It became a lovely activity that we would do."
Despite the lengthy audition process, in truth director Ben Caron was smitten with Emma from the first time he saw her. "When Emma stepped into the room, she had that amazing quality of vulnerability and strength," he says.
"And she looked like her, which often in the past we've reacted against because we've certainly not been a show that wants to do look-a-likes, and instead find the best actor that inhabits that character.
This was the first time we had an actor who can absolutely inhabit the essence of Diana, but also look scarily like her.
"That was really terrifying because it was like the ghost of Diana had stepped into the room, and that responsibility on essentially an unknown was huge.
However, what was attractive to us was finding an unknown actor and giving them the same experience that Diana would have had, going from being unknown to becoming the Princess of Wales."
When she finally landed the role Emma immediately called her mum. "It felt like a joint effort because she was just as invested as I was," she laughs.
At first, Emma confesses, she was daunted with the task of recreating the global icon and mother to Princes William and Harry. But when she received creator Peter Morgan's brilliant scripts, Emma started to relax.
"It's important to be reminded that The Crown is fictional and these are our versions, our interpretations of the characters."
"You have to step away from all the hot air and noise around these public figures, and when I got the scripts and started working on my interpretation of Diana, that's when I really began to be able to see past the pressure," she says.
Emma worked tirelessly on Diana's voice and mannerisms; the way she cocked her head, her doe-eyed gaze upwards, her impish sense of fun and her wells of inner sadness.
"Our Diana has these two parts in her that are constantly conflicting," she explains. "One is her spirit and her strength and one is her weakness and vulnerability and you constantly see those parts at odds with each other."
"And the fact that she has to perform, she has to do her duty, she has to turn up. She has to be a mother, she has to be a wife and all the time she's battening so much on the inside."
"I think Peter writes that kind of thing very, very well. I think it's why The Crown has done so well in the past. It's because his characters are so nuanced and so multifaceted and you get a complete 360 [degrees] of their experience – all the highs and all the lows."
To unlock the inner Diana, Emma watched Diana In her Own Words over and over and over. The controversial 2017 TV documentary features previously unseen private tapes of Diana pouring out her heart as she works with a voice coach in the early 1990s.
"I was so appreciative and blown away by her candidness. She was very willing to talk about herself honestly and in a very unguarded way that I thought was incredibly refreshing," says Emma.
"She talks about her mental health in such a candid way. For someone like her to do that, I think she was incredibly ahead of her time … I also wondered to myself if she was desperate to feel understood, she wanted so badly to share her side of the story. In our portrayal of Diana in The Crown she suffers from such intense loneliness within the royal family."
Series Four covers the years from 1979 to 1990. At the beginning we see a naive, giggly, engaging teenage Diana, hailing from one of the grandest aristocratic families in the land, meeting Prince Charles when he is dating her elder sister Sarah.
Diana is besotted and later, after a brief courtship, Charles proposes. The 20-year-old virgin marries the 32-year-old heir apparent and the rest is history.
A replica of Diana's famous wedding dress was painstakingly recreated by the costume department, and when Emma walked on set in the gown with its endless train, the crew got goosebumps.
"The wedding dress was a huge, huge thing. It went on very gradually and there were so many fittings for hours," says Emma. "When I put my wig on, it was almost quite terrifying because the significance of that image for people is massive."
"It was a weird moment, when we were filming that scene in these three huge rooms, the crew were all sitting up at one end and at the other end, I had the ten people trying to put me in this dress with the train, which was so long, and no one had seen me and then these doors open [and] everyone fell silent."
WATCH BELOW: Take a look at the costuming for The Crown:
Even before the wedding, cracks are starting to appear in Charles and Diana's relationship.
The interpretation by Peter Morgan is that Prince Charles' continued relationship with Camilla is a significant factor in the breakdown of the marriage but it's not the only thing.
For Morgan, Charles and Diana want the same thing – they both want to be loved and needed. It's a fascinating interpretation.
I ask Emma if she feels the couple could have lasted if Camilla hadn't been what Diana infamously called the third person in the marriage. "It maybe would have given them a chance," she suggests.
"I don't think they stood a chance whilst Camilla was in the picture. But I think ultimately they were very, very different people, although they shared a fondness and a love for one another that is undeniable."
The most joyous moments between the royal couple happen when they're on tour in Australia with baby Prince William.
Although it looks like Uluru and Woomargama, the NSW sheep station the family used as a base, the episode was actually filmed in Almeria and Malaga in Spain.
But even though we are not truly in Australia, viewers who look closely will see The Australian Women's Weekly in a couple of shots.
The Crown producers called The Weekly to ask for permission to mock up some vintage covers featuring their Diana, Charles and baby William.
Emma says the Australia episode is pivotal in the arc of Charles and Diana's relationship.
"I think being away from England, the royal family and Camilla gave them their own space."
"It's very rare that they are living in the same house as William together and when you see Charles and Diana on that ranch where they have time, they're at their happiest, I think."
"For a split second watching that you are really rooting for them and thinking 'oh my god could it work?', completely forgetting for a moment what the ending is."
The scene where the couple famously ripped up the dance floor at a ball in Sydney is mesmerising.
In Peter Morgan's script Diana's journey is certainly an emotional roller-coaster, covering her continued bulimia, her intense loneliness and then her attempts to woo her husband.
She dances to Billy Joel's 'Uptown Girl' with ballet star Wayne Sleep for her husband's birthday and sings a number from The Phantom of the Opera.
"There were intense days, especially with Diana, it's so dark so much of the time," admits Emma. "I remember there were two days in a row, with the dance and then the song that Diana performs for Charles."
"On the second day we did the song and they got in the actual West End cast to support me. I can sing, but I hadn't done it for a while and it was incredibly exposing to be on this stage with these professionals."
"The tempo of the music was different to the version I had learnt so it was terrifying …At the same time, this is the scene in which Diana goes through something hugely emotional, this is her reaching out to Charles to show him she loves him, and I very nearly couldn't do it."
We see Diana crumbling but also growing up and finding her voice. "You have these two things running in parallel – the mounting tragedy of her marriage failing, and also her growth and popularity and celebrity in the world," explains Emma.
Would Emma have been friends with the Diana she portrays? "I would have loved to have been friends with her," she laughs. "She was so fun. I've spoken to a few people who knew her and that's mainly the thing that they say. I wanted to bring that across in my portrayal, to show that youthful spirit."
In the next season of The Crown Australian actor Elizabeth Debicki takes over the baton as Diana for what will undoubtedly be the saddest chapter of Diana's life.
I wonder if Emma is ready to let her Diana go. "I wish I could [go on]. I am very, very fond of the role and her. But actually I think sometimes it's good to leave it if you've had a good experience and I think Elizabeth will do it so well."
Rest assured we'll be seeing much more of Emma Corrin.
The Crown Series Four is on Netflix on November 15.
See the full article in the December issue of The Australian Women's Weekly, on sale now.