Transcript for Inside Prince Harry, Meghan Markle's engagement and the story behind the proposal
Reporter: It's a love story made for the movies. American actress Meghan Markle newly engaged to Britain's most eligible bachelor, prince Harry. How are you guys feeling? Thrilled. Reporter: Their engagement breaking all the traditional rules of the British monarchy. Meghan is divorced, from a mixed race background, and an American commoner. Just an amazing surprise. It was so sweet. Reporter: In their first ever interview together the couple gushed about that magical moment Harry popped the question during a quiet night in while making dinner. 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 was like can I say yes now? She wouldn't even let me finish. Then there was hugs, and I had the ring in my finger. I said can I give you the ring? He should said oh, yes, the ring. Reporter: It's a big moment for the young prince, that little boy who we all watched grow up, always smiling by his mother's side, and then unforgettably standing beside his brother. Prince Harry paid tribute to his mother Diana in the engagement ring he gave to Meghan. A three-diamond stunner. The main stone itself I stored from Botswana. And the little diamonds on the side are from my mother's jewelry collection to make sure she's with us on this crazy journey together. Obviously, not being able to meet his mom, it's so important to me to know that she's a part of this with us. Reporter: The pair only started dating about a year and a half ago. We first met, we were introduced actually by a mutual friend. It was definitely a setup. It was a blind date. It was a blind date. I'd never even heard about her until this friend said Meghan Markle. I was like, right, okay, give me a bit of background. I was beautifully surprised when I walked walked into that room and saw her. There she was sitting there. I was like, okay, I'm really going to have to up my game. I had one question. I said is he nice? Because if he wasn't kind it just didn't -- it didn't seem like it would make sense. And so we went and had a -- met for a drink and I think very quickly into that we said what are we doing tomorrow? We should meet again. I think about three, maybe four weeks later that I managed to persuade her to come and join me in Botswana, and we camped out with each other under the stars. Reporter: The 36-year-old actress is no stranger to the spotlight, starring in the TV legal drama "Suits" for the past seven seasons. I want to get married. But I also really care about what I do. Reporter: Showbiz is in Meghan's blood. Born in Los Angeles, her father Thomas is an Emmy award-winning lighting director. Her mom, doria-s a social worker and yoga instructor. They split when she was just 2 years old. But she told "Vanity fair" in September, "I never saw them fight. We would still take vacations together. My dad would come on Sundays to drop me off and we'd watch "Jeopardy" eating dinner on TV trays, the three of us. We were still so close-knit." On social media Meghan often posts throwback photos of her parents. Meghan comes from very humble beginnings. This is probably one of the most ordinary families that we have seen marry into such a high level at the royal family. Reporter: Markle attend an all girls catholic high school before heading off to northwestern university double majoring in theater and international studies. She returned to California landing minor guest roles on shows like "General hospital" and "CSI." But I didn't kill him. Reporter: But she got her big break cast as a regular on "Suits." And I get it. I'm not good enough. What I don't get, Mike, is why you didn't have the courage to just come and tell me that yourself. With the filming schedule it was not the easiest because it of course included a lot of travel back and forth. You had -- the last year and a half. No. Reporter: But despite Meghan's on-screen presence all the attention that comes with dating a prince was overwhelming. I tried to warn you as much as possible but I think both of us were totally surprised by the reaction. There's a misconception that because I have worked in the entertainment industry that this would be something I would be familiar with, but we were just hit so hard at the beginning with a lot of mistruths that I made the choice to not read anything. Reporter: Meghan became 2016's most googled actress. Amidst all the chatter online there were some who went after Meghan's ethnicity. Her mom is black. Her dad is black. Of course it's disheartening. At the end of the day I'm really just proud of who I am and where I come from. And we have never put any focus on that. Reporter: There was also attention in the tabloids about the fact that Meghan has been married before, to film producer Trevor Engleson. Not long ago that kind of back story would have prevented a royal engagement. Back in 1936 king Edward VIII abdicated the throne because he wanted to marry Wallis Simpson, a divorced American, paving the way for his brother, king George VI -- Long may he reign. Prince Harry's great grandfather. The scandal immortalized in the oscar-winning film "The king's speech." A few hours ago I discharged my last duty as king and emperor. The empire was horrified at the idea that they were going to have an American as queen empress who had been divorced and this was not acceptable. Nobody cares about that stuff now. Reporter: Meghan says she's felt very welcomed by the royal family. The official announcement coming from her soon to be father-in-law prince Charles. No, we're thrilled, thank you very much. Reporter: She's even met the queen. It's incredible. I think, a, to be able to meet her through his lens, not just with his honor and respect for her as the monarch but the love that he has for her as his grandmother. I've been sitting here for a period of time when I literally didn't tell anybody at all, and then William was going to meet her and so was Catherine. So you know, they're neighbors. We managed to get out a couple of -- quite a few times now. And Catherine's been absolutely -- Wonderful. Amazing. Reporter: Meghan's parents also approving of the match despite all the unexpected attention. Well, I'm sure the onset, both my parents and my close friends were concerned, but they also had never seen me so happy. And I think also once my friends were able to really meet Harry and my mom, who we spent a lot of time with, it was so much fun. Your mom's amazing. He's talked to my dad a few times. It's been worth the effort. Reporter: As for what Diana would have thought about Meghan -- I think she would have been over the moon jumping up and down so excited for me. But then as I said would have probably been best friends, best friends with Meghan. It is days like today when I really miss having her around and miss being able to share the happy news. But you know, with the ring and everything else going on I'm sure -- She's with us. I'm sure she's with us, yeah. Reporter: Like Diana prince Harry is hugely popular, at home in the uk and around the world. Prince Harry is after the queen the most popular member of the royal family. If Harry plays it right with Meghan the two of them could be the superstar Royals. Reporter: That could be in part thanks to his, shall we say, less formal public persona. While the now 33-year-old is ready to settle down, in his 20s Harry was much more likely to make headlines as a wild child. The playboy prince. Starring in some of the royal family's most embarrassing headlines like the time he was photographed at a party in las Vegas naked. Actually, we're worried now that he might become a bit boring like his brother if he just settles down and sits down in jumpers eating again Bolognese. Reporter: Harry admitted all that behavior was in part a reaction to losing his mom. I really regret never talking about it. For the first 28 years of my life. Never talked about it. Reporter: In a candid interview with my colleague robin Roberts he opened up about how Diana's death changed him. I think losing your mother at such a young age does end up shaping your life massively. Of course it does. And now I find myself trying to be there and give advice to other people in similar positions. Reporter: He went about rehabbing his image, focusing on his military background. Ten years in the British army, including two tours in Afghanistan. In 2014 he launched the invictus games for wounded warriors. You have done it. You are invictus. Reporter: Harry and Meghan made their first public appearance at this year's invictus games. Humanitarian work has long been a focus for her too. And she says it's a big part of what drew them to each other. I think that's what got date two in the books probably. Reporter: Meghan will be giving up her acting career for a bigger role on the global stage. I think what's been really exciting is we talk about the transition of this out of my career but into the role is as you said the causes that have been very important to me I can focus even more energy. It's not easy for anybody. Whatever we have to tackle together or individually will always be us together as a team. The wedding will take place sometime this spring. Royal watchers wondering if they may hold out for a late spring wedding after the duchess of Cambridge gives birth to her third child in April, which of course begs the question, children? Not currently, no. No, of course, one step at a time and hopefully we'll start a family in the near future. Reporter: For "Nightline," Terry Moran, London.
This transcript has been automatically generated and may not be 100% accurate.