Why 'The Crown' Made Princess Diana's Bulimia a Major Part of Her Story in Season 4

The Crown Season 4-Princess Diana (EMMA CORRIN)

When Princess Diana opened up in a 1995 interview about her struggle with an eating disorder, she called it a "secret disease" that she'd dealt with for years. It began just after she and Prince Charles were engaged, she said, and took nearly a decade before she was able to overcome it.

It's because of how open Diana herself was about her battle that Emma Corrin, who plays the late royal in the fourth season of The Crown, wanted to make sure the Netflix series would tackle it openly and explicitly.

"I, through my research, realized that she was very candid about it and I was really impressed. I thought that that was massively ahead of her time," Corrin told The Hollywood Reporter. "If you think about it, even these days if a public figure comes out and says something about that as their experience it makes headlines. It has journalists going wild to want to find out what happened. Everyone's so celebratory of people sharing their experiences and it's such a good thing these days. And she was doing that in the '90s, which is incredible. I wanted to do it justice."

That meant no casual allusions to the problem — over the course of many episodes Diana can be seen explicitly in the bathroom as she struggles with the disease. That's because Corrin worked with the writers and creator Peter Morgan to highlight the kind of all-consuming effect that bulimia would've had on Diana's life.

"Bulimia and self harm, these are experiences that, when they're happening to you, are at the center of what you're going through," said Corrin. "They are symptomatic of so much, but also they cause so much of your behavior as well."

After Corrin got the scripts, she worked with her movement and character coach, Polly Bennett, to flesh out that side of the story. They spoke with charities, went on online forums, and read plenty of books, then delivered a giant Word document to the writers to help flesh out the scenes involving the disease — and to include more of them.

"I don't think you can separate it from what's going on. It was the way she dealt with what she was feeling and therefore it contributed to the way she was feeling," she said.

Corrin, who was born in 1995, had none of her own memories of Princess Diana, who died in 1997. Instead, she says, she "had this awareness of her as this very generous, humanitarian person." And someone who cared so deeply about others would want to make sure that others who suffered from the disease were properly warned about the content they were going to consume.

Part of responsibly portraying someone's relationship to an eating disorder is warning others that the episodes will include potentially triggering content. While Netflix learned the hard way about including such warnings after the first season of 13 Reasons Why, the streamer took no such missteps when it came to this episode.

"If we just alluded to it, you saw her flushing a toilet or you saw her wiping her mouth and it was like, 'is she suffering from bulimia?' I think that people who have suffered from it would probably think, 'come on, are they just not going to show it? Why aren't they going to show it?' So many people go through this," Corrin said. "We should be talking about it. And Diana talked about it. We needed to show it and I think as much as I hope people who have experienced it will be glad that we've showed it, also it obviously is triggering and so I think it's important that disclaimers are there at the same time."