Transcript for Royal wedding ushers in a new era for the monarchy: Part 1

Harry and Meghan's relationship really is a fairytale. ??? I'll never let you go ??? Reporter: An elite few have had that dream come true -- the dream of marrying a prince. Four decades ago it was princess Diana and now it is American Meghan Markle. The relationship works with Harry, because I think probably Harry recognizes something of his mother in her. Reporter: Princess Diana and Meghan Markle born worlds apart they would never meet and yet, they're the two most influential and important women in prince Harry's life. When the newest royal couple met times had changed significantly for the British monarchy. It makes me smile in a way. You want to listen very carefully when the choir's singing tomorrow, because there'll be another sound. And it'll be the sound of the duke of Windsor, who's buried at frogmore quite nearby, spinning in his grave. Reporter: That's because Edward, the duke of Windsor -- as portrayed in the Netflix series, "The crown" -- abdicated the throne to marry his divorced, American fiancee Wallis Simpson. Is she really worth it? I love her with all my heart. Reporter: That meant queen Elizabeth's father was crowned king George. But that was 80 years ago when obligations to queen and country trumped marrying for love. It genuinely is a different age. Reporter: Andrew Morton's latest book is titled, "Meghan: A Hollywood princess." We have a biracial, divorced woman about to become her royal highness. So it shows you how what a remarkable transformation we've seen in this reign. Meghan is a feminist, part of the me too movement. There's no better time to shine a light on women feeling empowered. The words "Breath of fresh air" is often used in connection with the royal family in terms of Meghan Markle. It's absolutely true. Reporter: At 36, Meghan is three years older than her husband-to-be. She was a successful actress with a dual degree in theater and international relations from northwestern university, when a friend set-up her up on a blind date with Harry, prince of Wales. And so we went and had a -- met for a drink and then I think very quickly into that we said, well, what are we doing tomorrow? We should -- we should meet again. Reporter: The couple wasted little time. Within weeks they traveled to Africa for their third date. Africa is somewhere that has been really important to Harry all of his life. And has been incredibly important in his and Meghan's relationship. It was on a trip to Botswana, just a few weeks after they met, that they really fell in love. Reporter: Meghan's royal "Wooing" was far cry from Harry's mother, lady Diana Spencer, who was a teenage nursery school teacher when she began seeing prince Charles, heir to the British throne. They had met each other 13 times before they got engaged. She called him "Sir," up until the point where they got engaged. Prince Charles, I think, was looking for more for a companion to take on his duties than someone who would be a lover. What was your instant impression? I remember thinking what a very jolly and amusing and aye attractive 16-year-old she was. Reporter: In their official engagement interview, a shy Diana looks on as prince Charles does most of the talking. Until Meghan came on the scene, a royal girlfriend would say nothing. And would go through the ordeal of the Paparazzi, being chased down the street. Diana felt she'd been thrown in the deep end. It was a challenge. Reporter: Diana would later discuss this in her famous bbc news panorama interview. I was very daunted because, as far as I was concerned, I was a fat, chubby 20-year-old -- 21-year-old -- and I couldn't understand the level of interest. The media were everywhere. It was isolating, but it was also a situation where you couldn't indulge in feeling sorry for yourself. You had to either sink or swim. And you had to learn that very fast. Reporter: At 20 years old, Diana rose from relative obscurity to become the most photographed woman in the world. Already in her mid-30s, Meghan Markle came into her engagement with media savvy, an actress and influencer with millions of social media followers. She's a woman who's very much at ease with herself, at ease with the camera. Everything was just perfect. Reporter: That was evident in their engagement interview as Meghan and Harry tell the story of his proposal. Just a cozy night, it was -- what we were doing just roasting chicken and having -- Roasting a chicken, trying to roast a chicken. Trying to roast a chicken and it just -- just an amazing surprise, it was so sweet and natural and very romantic. He got on one knee. Of course. Was it an instant yes from you? Yes, as a matter of fact I could barely let you finish proposing. I said, "Can I say yes now?" She didn't even let me finish. Then there was hugs. Reporter: The engagement Reporter: The engagement ring a diamond from Botswana and two from the collection of Harry's mother Diana. I think everything about Harry's thoughtfulness is -- and the inclusion of that and obviously not being able to meet his mom. It's so important to me to -- to know that she's a part of this with us. William and Harry have what is often called a "Smiling hatred" of the media. They believe the media killed their mother. It's something they have to deal with. And for Harry, it has to be a huge relief to finally meet somebody who's at ease in front of the cameras. Reporter: Joining the royal family means Meghan must actually dial back her public presence, giving up her acting career and shutting down her personal social media accounts. She's given up an awful lot. And what does she get back in exchange? Anything she gets involved the world takes notice. So she can make a genuine difference. Meghan is someone who, like Diana, is so strong-willed in her beliefs, who leads with the heart, who isn't afraid to speak her mind. Harry really needed that person to marry. He needed a team member. And that's what Meghan is. She's a team member in the most famous family in the world.

This transcript has been automatically generated and may not be 100% accurate.