It's the world's first glimpse of the little prince.
Kate and William, both dressed in baby blue, finally appeared at 7:14 p.m. London time carrying the one-day-old future king.
Kate tenderly passed her son to William. She wore a polka dot dress over her still-swollen belly.
Prince William told reporters, "He's got a good pair of lungs on him, that's for sure. He's a big boy. He's quite heavy."
Kate said, "It's a very emotional and special time. I think for any parents probably know what this feeling feels like."
William joked about the baby's hair.
"He's got way more than me, thank God," said Prince William. "He's got her lips, thankfully."
But they stayed mum about the royal heir's name.
Prince William said, "We're still working on a name, so we'll have that as soon as we can. It's the first time we've seen him really, so we'll have a proper chance to catch up."
It's a milestone celebrated by all new parents, bringing their baby home from the hospital. William put the car seat in their Range Rover and got behind the wheel to drive his son home himself.
Earlier in the day, the crowd cheered on a beaming Prince Charles as he visited his grandson for the first time.
"He's marvelous, thank you very much," said Prince Charles.
Kate's beaming parents, Carole and Michael Middleton, also gushed about their new grandson.
"He's absolutely beautiful," said Carole.
A reporter asked, "Have you given them any suggestions on a name?"
"Absolutely not," replied Carole.
Bookmakers in London are now saying James is the favorite, followed by George and Henry. As for his formal title, it's His Royal Highness The Prince Of Cambridge.
During the day, all comings and goings at St. Mary's Hospital came under the eyes of the world.
A royal staff member arrived carrying a car seat for the baby prince. Kate's official hairdresser also arrived. A garment bag was delivered to the hospital holding the dress that Kate wore to introduce her baby boy to the world.
CBS News London correspondent Elizabeth Palmer reported, "You can see why Kate will want to look best. It would be very intimidating to come out of the hospital right after giving birth to what must be said was a big baby, and face these ranks and ranks of video cameras and still cameras."
Reporters braved an intense downpour, typical of London this time of year. It soaked the team from Good Morning America.
A 41-gun salute in London was just one of the celebrations for the royal heir.
A jaw-dropping 487 million people tweeted the news of the birth.
The front page of The London Sun became The Son. "It's A Boy!" announced multiple newspaper's front pages, and The Mirror exclaimed: "Our Little Prince."
The prince could be the first reigning British monarch of the 22nd century. In the year 2100, he'd be 87 years old, the same age that Queen Elizabeth is now.
At the New York City premiere of the Woody Allen movie Blue Jasmine, another famous Kate, Cate Blanchett, expressed support for the royal family.
"I hope she's well and healthy," said Blanchett.