Transcript for Prince Harry and Meghan Markle set date for wedding

And we have a lot of news to get to tonight. First, that global headline. The daughter from America about to join the royal family. Prince Harry asking Meghan Markle to marry him. Tonight, where he asked her, the history. The first American to officially join the royal family. She was raised in a biracial family. She went to a catholic high school here at home. She's now an actress. Tonight, what it was like the first time in the room with the queen. This evening, their first interview being watched all over the world. And here's ABC's chief foreign correspondent Terry Moran. Reporter: Hand in hand, they stepped into the sunken garden at kensington palace, prince Harry and Meghan Markle. Almost giddy, it seemed. How are you both feeling? Yeah, thrilled. Meghan, how are you feeling? So happy. Reporter: And later, they talked about the big moment Harry popped the question. It happened a few weeks ago, earlier this month, here at our cottage. Just a standard, typical night for us. 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. Can I say yes, can I say yes? Reporter: For months, they've been the focus of speculation. But today, they just seemed like two young people, happy in love. At the end of the day, she chooses me and I choose her and therefore, you know, whatever -- whatever we have to tackle, together or individually, will always be us together as a team. So I think -- I think she's capable of -- That's so nicely said, isn't it? Reporter: And Meghan seems ready to become one of the family. Talking about meeting Harry's grandma, queen Elizabeth II, who gave her blessing. Meghan also addressing how her own family reacted. Do you think they have worried at all about the scale of what you're getting into? Well, I'm sure the onset, both my parents and my close friends were concerned, because we got very quickly swept up in a media storm that, as I shared, was not part of my life before that. But they also had never seen me so happy. Her mom's amazing. Reporter: They remembered how they met last year. It was definitely a set-up, it was a blind date. It was a blind date for sure. I didn't know much about him. And so, the only thing that I had asked her when she said she wanted to set us up was -- I had one question, I said, "Well, is he nice?" I'd never heard of Meghan before. And I was beautifully surprised when I -- when I walked into that room and saw her. There she was sitting there, I was like, okay, well, I'm really going to have to up my game. Reporter: All of it leading to that proposal and that ring. The ring is -- is obviously yellow gold, because that's what -- her favorite. And the main stone itself I sourced from Botswana and the -- the little diamonds either side are from my mother's jewelry collection, to make sure that she's with us on this, on this crazy journey together. And -- It's beautiful, and he designed it, it's incredible. 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 know that she's a part of this with us. And Terry Moran joinings now from London. And Terry, I remember being there, as William and Kate pulled out in that '69 Aston martin. Maybe a Ford mustang for the American princess. Who knows? Reporter: Well, no word on the car right now. But the palace has said that the wedding will take place next spring. That's going to be a very busy time for the royal family. Prince William and Kate are expecting their third baby in April. The betting here in London is a wedding in may, which may mean a convertible for the royal couple.

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