Toward the end of The Crown season four, which follows the lives of the British royal family between 1979 and 1990, Queen Elizabeth II (Olivia Colman) visits her daughter, Princess Anne (Erin Doherty), to try to understand why the marriage between her son, Prince Charles (Josh O’Connor), and Princess Diana (Emma Corrin) is failing.

“Once upon a time there was a beautiful young girl who fell madly in love with a handsome prince,” Anne explains to her mother. “Unfortunately, the prince was already in love with someone else, who was herself in love with someone else. And they all lived unhappily ever after.”

She is, of course, referring to the love triangle between Diana, Charles and Camilla Parker-Bowles (which is actually more of a love square, if you factor Camilla’s then-husband, Andrew Parker-Bowles, into it). And while “that’s it in a nutshell,” as Anne puts it, the season, which hits Netflix on November 15, explores the complicated reality –  including the 12-year age difference between Charles and Diana, Charles’ jealousy over the public’s warm reception of Diana and, yes, extramarital affairs on both sides – that factored into their separation in 1992 and eventual divorce in 1996.

Becoming Princess Diana 

Lady Diana Spencer, as we’re first introduced to her in the season, works at a kindergarten and lives with girlfriends in a flat in London. The role is played by 24-year-old Corrin, who looks uncannily like a young Diana. “There’s so much that goes into building this character: the wig and the makeup, and then the mannerisms and the voice and all of the research,” Corrin tells us. “It’s like putting a person together piece by piece.” (In seasons five and six, Princess Diana will be played by Elizabeth Debicki.)

Despite the similarities, Corrin is clear that this is her interpretation of the people’s princess. “There are a million documentaries people can watch if they want to see [the real] Diana,” she says, calling out In Her Words, which is comprised entirely of Diana’s own comments. “That’s not the point of this show.”

Season four covers Diana’s tumultuous relationship with Charles and the majority of their marriage – though, despite the incredible detail put into the creation of Diana’s wedding dress, it gets very little screen time. Corrin calls the weight of the dress, which took over 600 hours to make, “remarkable.” “It was beautiful,” she says. “To wear it on set and to act in it felt incredibly surreal.”

“She was candid about her mental health”

The season also delves into the impact joining the royal family, and all the scrutiny that entails, at age 20 had on Diana’s mental health ­­– particularly, her struggle with bulimia. According to Netflix, producers worked with BEAT, a U.K.-based eating disorder charity, to craft the storyline, which was developed around Diana’s personal comments about her eating disorder.

During her research for the role, Corrin was surprised to learn how candid Princess Diana was about her mental health. “We might take it for granted now, but back in the nineties, who was talking about mental health? Especially those in the public eye,” says Corrin. “It was amazing that she was so vocal about it.”

“We didn’t want to play the tragedy”

Corrin says playing the happiness of Diana’s life, including the initial love between Charles and Diana, was important to her.  “Josh [O’Connor, who plays Prince Charles] and I had to be very careful. We had to remind each other that we didn’t want to play the ending, the tragedy, and it was quite hard to do,” she says.  “I hopefully communicated that in her relationship with William and Harry, the joy that they brought her, and in the moments that she did think the marriage was going well.”

“When I spoke to her private secretary, one of the things he said was that she was such a naturally happy person, despite everything that was going wrong for her,” she adds.

“I hope [viewers] see a very balanced portrayal of a girl who was thrown into a situation she was completely unprepared for and how she grew through it and protected herself.”

READ MORE:

The Cast of  The Crown Discuss All Things Season 4

Your First Look at Princess Diana’s Wedding Dress in The Crown

The Crown Will Run For Six Seasons After All