Diana, Princess of Wales, was granted very little privacy during her years in the spotlight. Now, a new documentary is pulling back the curtain—or opening the family photo album, if you will—on the side of her life she worked hardest to keep to herself: her role as mother.
Diana, Our Mother: Her Life and Legacy, which debuted Monday night on HBO, is a polished contrast: It's a story told for the cameras about the part of one woman’s life that the cameras didn’t capture. Thanks to the involvement of her sons Prince William and Prince Harry, the documentary is intimate but selective; its view is rosy, but the pain is, to quote Harry, “still raw.” As the 20-year anniversary of Diana’s untimely death approaches, it seems there’s still plenty of grieving to do, for the brothers and the world.
Here are seven highlights—some emotional, others delightfully impertinent—from Diana, Our Mother.
1. Diana enlisted supermodels to embarrass her son
Harry describes his mother as a kid at heart (“I think she lived a lot of her life, especially in private, through us”), and both brothers recall her “cheeky” sense of humor. William in particular fell victim to Diana’s pranks. Not only did she send her eldest “the rudest cards you could imagine”—filled with loving sentiments, of course—but she even arranged to have a trio of supermodels (Naomi Campbell, Cindy Crawford, and Christy Turlington) waiting for him at the top of the stairs when he got home from school.
“I think I pretty much fell down the stairs on the way up,” says William.
2. Fashion wasn’t everything
Harry jokingly speculates that Diana dressed her sons “in the most bizarre outfits” just because she got a kick out of it. “I’m sure that wasn’t it,” he clarifies, “but I sure as hell am going to dress my kids up the same way.”
Even if she wasn’t putting her sons in matching outfits for a laugh, Diana did see the link between clothes and self-expression. A friend who met her when she was 14 years old describes teenage Diana “wandering around in jerseys covered in hippos” and says she liked to borrow his shirts.
Her personal stylist, Anna Harvey, remembers the way Diana’s divorce from Prince Charles gave her more freedom in the way she dressed. And William looks back on giving his mother the idea to give away her old clothes, leading to an auction for charity in June of 1997 that kicked off a new phase of her life—one in which she would force the media to pay more attention to what she was doing than what she was wearing.
VIDEO: Prince William and Prince Harry Released Private Unseen Family Photos
3. Diana’s advocacy lives on
Diana, Our Mother is at its most effective as it explores how Diana used her position to bring light to controversial social issues, from homelessness to the AIDS crisis to the campaign to end landmines. Everyone who worked with her in that capacity singles out her empathy.
“Most people want to get away from pain… they can’t be fully present in the presence of pain,” says University of Virginia Professor Jerry White, a landmine activist who accompanied Diana to Bosnia just weeks before her death. “And the Princess of Wales could be there.” While there, she met with young victims, like then-15-year-old Malic Bradaric, who today tears up as he credits Diana with not only giving him moral support but preventing future tragedies: “This is her legacy that there are no landmines here.”
Luckily, her legacy is carried on in her sons; both William and Harry have picked up Diana’s causes. The cameras follow William to a London homeless shelter and Harry to a meeting with Malic and fellow victim Zarko, who also met Diana during her trip in 1997. One of the most haunting lines of the documentary is Harry’s: “You saw my mother more recently than I did, I guess.”
4. Even Prince Harry is in awe of Rihanna’s social media presence
Harry has also picked up his mother’s crusade to destigmatize AIDS. Along with Elton John, the prince meets with two of the men Diana worked with at AIDS care center London Lighthouse; then, Harry travels to Barbados to promote blood testing with Rihanna. He’s as impressed by her Instagram following, as we all are.
5. The brothers’ last words with Diana were over the phone
The documentary is never more relatable than when William and Harry look back on an all-too-common phenomenon: the conversation with their mother that they didn’t know would be their last. She called them from Paris while they were at Balmoral Castle in Scotland, and each brother in turn spoke to Diana for a few minutes before rushing off. “If I’d known that that was the last time I was going to speak to my mother, the things I would’ve said to her,” Harry says.
When asked if he remembers what was said, William just nods, “I do,” intentionally keeping one memory just for himself. Growing up with his mother, he knows as well as anyone the importance of a barrier with the press.
VIDEO: Princess Diana Heard Prince Charles Tell Camilla He Would "Always Love Her"
6. The princes didn’t grieve as expected
After Diana’s death, Harry recalls watching the country mourn and wondering how so many people who didn’t know his mother could be showing more emotion than he was feeling. He says he cried for the first time when she was buried at her family home, and since then, “maybe only once.”
“So there’s a lot of grief that still needs to be let out,” says Harry. That might help explain why, when he and William sit down to look at photos of their mother, they say this is the first time they’ve talked about her like this. The conversation is awkward and earnest, and that’s not just because there are cameras present.
7. Prince George and Princess Charlotte hear all about Diana
William is “constantly talking about Granny Diana” in front of his children, and he and Kate have put more photos of her around their home. It’s important, he says, that the kids know “there are two grandmothers—there were two grandmothers in their lives.”
Were Granny Diana around, he lovingly adds, “she’d be a nightmare grandmother.”
This Story Originally Appeared On Entertainment Weekly