HELLO! Online chatted to some of the onlookers outside Buckingham Palace to find out what they thought the royal baby would be named, what Kate and Prince William would be like as parents, and how much of a "cool" uncle Prince Harry will be.
Thousands of well-wishers had already congregated outside the palace long hours before the birth was announced on one of the hottest days of the year in the hope of capturing the historic moment when the details of the royal baby were displayed on an easel behind the palace railings.
Find out what the crowds had to say to HELLO! Online's reporters.
Do you think the royal baby will be a girl or a boy?
"I think it's going to be a girl."
"I'm hoping for a princess."
"We're hoping for a boy."
"Either a boy or a girl — we just want a healthy baby."
What do you think the royal baby will be named?
"I don't know, but of course we'd love Diana for a girl."
"It should be a typical English name. It's common for royals to take after their ancestors, which could be cool, but maybe Kate and William will mix it up with a more modern name."
"It should be something traditional as they're both quite traditional. The name should be something after Catherine and William — it could be Willimina Catherina."
"Something not too traditional, a little different — not Apple or North, but not Elizabeth or Diana either."
"Charles for a boy, and Lola for a girl."
Alexandra is proving a popular name with the bookies. What do you think about that?
"Alexandra's a beautiful name."
"Alexandra's nice but I feel like a lot of royalty have that name — it's a little over-used."
What do you think about Kate and William keeping the gender a secret from the public?
"Their whole life is in the public eye so they can keep something for themselves."
"I think it's marvellous that they're keeping really low-key and they're so excited about their first baby together."
"I think it's lovely because it's more traditional."
What do you think Kate and William will be like as parents?
"I think they'll be great parents. William looks like a good guy. He looks like a nice person and Kate as well."
"Fabulous. Kate won't have a nanny, I'm guessing, and I think that's wonderful. She wants to keep the baby's life as normal as possible."
"I think they'll be modern parents. William will be doing the night nappy changes. They'll be hands-on."
"They'll be lovely parents. Modern, yet traditional and they'll raise beautiful children."
What do you think Prince Harry will be like as an uncle?
"I think he'll be a naughty, cool uncle — the one that gets them drunk on their 16th birthday. And he'll take them out with his sports car."
"I think he's perfect uncle material. He'll be really fun."
What kind of advice would you give Kate and William about being parents?
"Just enjoy every moment. It goes by so fast."
"Congratulations and enjoy it. Enjoy them while they're young."