Transcript for Diana's ex-bodyguard on the princess's willingness to break from royal tradition
She was among the most famous women of her time, hunted by Paparazzi, living her private life very publicly. And yet nearly 20 years after her death we continue to learn more and more about princess Diana. Here's ABC's James Longman. Reporter: Before she became the people's princess she was just Diana. My earliest memories of her, she always had a sort of natural star quality. She could strike a pose in clothes she had borrowed from my eldest sister. When Diana was a little girl, she starts to realize how people fall in love with her. She was one of those children that goes into the room and everyone is charmed by her. Reporter: This rare footage part of the story of Diana, a new documentary celebrating her life and mourning her loss 20 years later. It was a fairy tale. It became a soap opera. And it ultimately became a tragedy. Reporter: Before reality television, before social media, she defined what it meant to be a modern celebrity. Can you describe what people call the Diana phenomenon? When she walked into a room, she lit the place up. More than any other royal I've ever experienced. Reporter: At just 20 years old she married the future king in what many called the wedding of the century. It was a global television event. 1/6 of the world watched live. Diana dazzled the world as the new royal princess. But it was her human, common touch that set her apart. Well, we'd had royal walkabouts before. The queen was pretty good at doing them. In New Zealand she mingled with her subjects. When she does a walkabout it's sort of staying back from the crowd. She won't go right up to the barrier and reach in. She'll stand back and she'll extender arm out and take some flowers. It would be very I'm here and you're there. With Diana it was completely different. If there was a small child with some flowers, Diana would go down low to the child's level. Reporter: Her willingness to break from tradition was no different when she became a mother, as chronicled in the film. May we see your son, your royal highness? In the past royal children were confined to nurseries, looked after by nannies. Diana didn't want that for her children. Reporter: Ken wolf, princess Diana's former bodyguard, saw firsthand how she stepped outside traditional royal boundaries. She was fun. And she was very keen to break the rulebook here in terms of royal children. They would come back completely buoyed up having had a great afternoon with their mates at a burger bar. Covered in barbecue sauce. Exactly. The prince would say where have you been? We've been to a great burger bar in kensington high street. Their mother would stand there laughing. He's say why? We have a perfectly good chef. Didn't get the point. But for Diana it was the point, of what other people did. Reporter: With cameras constantly following, she was fiercely protective of her boys. In the film we see the princess pleading for a moment of privacy on a ski vacation. As a parent could I ask you to respect my children's space? Because I brought the children out here for a holiday. And we'd really appreciate the space. I understand that. And I'm sure -- Would it be possible to just get -- No. Reporter: And behind the scenes drama of a different sort. A fight for prince Charles's heart with Camilla parker-bowles, the woman he never gave up. Whav saw the princess's heartbreak up close. She did love the prince of Wales. I could see the anguish. I could see the unhappiness. Reporter: That strife played across millions of television screens. From the prince's admission in an itv documentary -- It became irretrievably broken down. Reporter: -- To Diana's well-known 1995 bbc interview. Well, there were three of us in this marriage. So it was a bit crowded. Reporter: This interview the final straw for the monarchy. The queen has sent a letter to her son, prince Charles and his estranged wife, Diana, the princess of Wales, asking them to get a divorce, and soon. Reporter: But possibly, despite the wishes of the palace, Diana remained in the spotlight. They kick you out, like they're going to need a deep sea diver to find you. But nobody's going to play Diana like that. Reporter: Continuing to use the attention to shed light on issues like AIDS, homelessness, and landmines. There would not be necessarily a George Clooney or an Angelina Jolie or this responsibility that celebrities feel to take the spotlight that's turned on them and turn it onto other causes. Reporter: But the fascination also remained with her personal life. All the ironies about Diana, perhaps the greatest was this. A girl given the name of the ancient goddess of hunting was in the end the most hunted person in the modern world. Diana, the princess of Wales, has just died. Reporter: She was killed in a Paris car crash after being ending her story mid-chapter. 20 years later princess Diana has left an indelible mark in the public consciousness and on the royal family. She has transformed the monarchy, and I think prince William's reign as king after that of prince Charles will be more of a Diana reign than, say, an Elizabeth reign. I love the fact that there's still such veneration inside her immediate family for what she was and what she meant. And I think that's fantastic. Reporter: For "Nightline" I'm James Longman in London. The story of Diana, the two-night event, starts tomorrow right here on ABC at 9:00 P.M. Eastern.
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