Transcript for Prince Harry and Meghan Markle welcome baby boy
in the line of British Royals. A prince beaming with that familiar awe of a new dad. Meghan and myself had a baby boy early this morning. A very healthy boy. Mother and baby are doing incredibly well. Reporter: Prince Harry and duchess Meghan Markle's firstborn son arrived at 5:26 A.M., weighing 7 pounds 3 ounces. It's been the most amazing experience I could never have possibly imagined. How any woman does what they do is beyond comprehension. But we're both absolutely thrilled. Oyez, god bless America and god save the queen! Windsor has gone crazy ever since the announcement. There are people and cameras everywhere. And it is just absolute madness. Reporter: My colleague will reeve has been in Windsor anticipating the birth alongside royal fans. It's wonderful! Reporter: The birth, historic. People have been camping out as well, sleeping in sleeping bags waiting for the news and stuff. Yeah, waiting for everything. Yeah. Reporter: The baby the product of a first interracial marriage in the British monarchy that dates back more than 1,000 years. Baby Sussex is going to be one of the most famous children in the world and be scrut newsed, in and out least because baby Sussex is the product of the first globalized world marriage and is going to be half American. Still thinking about names? Still thinking about names. Yeah, the baby's a little bit overdue so we've had some time to think about it. Yeah that's the next bit. Reporter: He's the queen of England's great grandchild and seventh in line to the throne after Kate and William's They are very unlikely to become a full-time working royal when they grow up. Reporter: The couple announces they'd been keeping the plans around the baby's birth private. A statement from Buckingham palace saying, the duke and duchess look forward to share the exciting news to everyone once they have had the opportunity to celebrate as a private family. It's interesting how the duke and duchess of Sussex have chosen to play this. He'll use to it protect his wife and now his little boy. Reporter: Privacy wasn't an option for prince William and Kate Middleton's first child, prince George. The duke and duchess of Cambridge duty-bound to present the next heir to the throne to the world only hours after he was born. Long before Harry met Meghan, the prince made no secret about wanting to become a dad. I adore kids. I enjoy -- I enjoy everything that they bring to the party. They just say what they think. The way you talk about children, is it something that you think about in the near future or down the road? I think the advantage is being an uncle before having your own kids, means you can learn a lot and a lot of my friends have got kids at the moment. So I'm making the most of learning as much as possible, and actually I can't wait for the day. Reporter: Fate intervened in the summer of 2016 when a mutual friend set Harry up with Meghan, an American actress best known for her role on the TV show "Suits." I couldn't have done it without you. You wouldn't even know where to look without me. I had one question, is he nice? If he wasn't kine, it didn't seem like it would make sense. I was beautifully surprised when I walked into that room and saw her, there she was sitting there. Wow, I really have to up my Reporter: Just a few months into their budding relationship, British tabloids descended on them with racially charged headlines and commentary, like this one from "The daily mail" that read, Harry's girl is almost straight out of Compton. She's been subject to incredible online abuse, as has Kate Middleton, but I think there is this component of race that Harry addressed even before they were married. Reporter: Prince Harry defended Meghan in an unprecedented royal statement calling out the racial undertones of comment pieces and the outright sexism and racism of social media trolls. It's a shame that that is the climate in this world, to focus that much on that, or that that would be discriminatory in that sense. But I think, you know, 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. We've just focused on who we are as a couple. Reporter: A year and a half after they first met, prince Harry put a ring on it. Their wedding in many ways unprecedented. Meghan Markle has broken most stereotypes of what we thought of as British royalty. She is American, so that's its own bridge. She is biracial, another bridge. Reporter: The day captivated both Brits and Americans. 29 million people tuned in to watch it live, and more than 100,000 well-wishers lined the streets around Windsor. Then, just five months later -- Bombshell royal news, duchess Meghan is expecting a child. Reporter: Pregnancy didn't stop the couple from continuing to travel around the world, in service to the causes they hold dear. Like championing girls' education in rural Morocco just this past February. Their humanitarian work reminiscent of another royal. Prince Harry's late mother, princess Diana. She used her fame to focus the world's cameras and compassion on issues like homelessness, leprosy, and hiv/aids. HIV does not make people dangerous to know. So you can shake their hand and give them a hug. Heaven knows they need it. Diana was all about making the monarchy more approachable and accessible, and I think Meghan and Harry are breathing into that. What do you think your mother would have thought about Meghan or said about Meghan? They'd be thick as thieves, without question. I think she'd be over the moon, jumping up and down, so excited for me. But then as I said, we'd probably have been best friends, best friends with Meghan. The world has watched prince Harry, the son of princess Diana, grow up. We've lived and breathed the highs and lows him. I think for so long people have wanted him to have his own fairy tale happy ending. I'm incredibly proud of my wife. As any father or parent will say, your baby is absolutely amazing. But this little thing is to die for. I'm just over the moon. Reporter: As for when we'll see a first glimpse of their newborn? We'll be seeing you guys in probably two days' time as planned, as a family, to be able to share it with you guys, so everyone can see the baby. Reporter: The world will just have to wait a little longer. And our warmest congratulations to the new mom and dad. Up next, more is better.
This transcript has been automatically generated and may not be 100% accurate.