The royal couple looked overcome with emotion as they were greeted by huge cheers and applause from the crowd of well-wishers and international media who had gathered outside the hospital's Lindo Wing.
The Cambridges proudly posed for photographs outside the Lindo Wing with the sound of hundreds of flashbulbs fluttering in the background.
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The Prince of Cambridge was passed from his mother's arms to his father's as the new parents went to talk to the euphoric reporters who had waited for weeks for the historic moment.
"We've still got to decide on a name," William said to reporters. "We'll let you know as soon as we can."
"We're very emotional," said Kate, dressed in a bespoke cornflower blue crepe de chine dress by British designer Jenny Packham. "It's such a special time."
"He's got a good pair of lungs on him that's for sure," William joked. "He has got Kate's looks thankfully.
"I'll remind him of his tardiness when he's a bit older," he told the assembled media. "I don't know how long you guys have been here now, hopefully the hospital can get back to normal."
"He changed the first nappy," said 31-year-old Kate.
The baby Prince was just one day old — delivered at 4.24pm on Monday 22 July — and was blissfully oblivious to the fuss that his arrival had caused.
Kate, despite her tiredness, looked radiant as she held her precious son and posed for photographers. Images of the young family were instantaneously beamed around the world.
"The Duke and Duchess of Cambridge and their son will travel home to Kensington Palace," a Palace statement read.
"Their Royal Highnesses would like to reiterate their thanks to the hospital for the care and treatment they have all received."
With the precious little boy safely strapped into his car seat, William drove his wife and son back home in a Range Rover. New aunt Pippa Middleton and her boyfriend Nico Jackson were waiting just minutes away at Kensington Palace to meet the baby.
In addition to the bustling crowds of photographers, cameramen, reporters and well-wishers, even hospital staff had gathered to catch a glimpse of the baby Cambridge.
The picture of Kate, William and their newborn son was reminiscent of that of Charles and Diana introducing Prince William to the nation when they stood on the steps of the same hospital in 1982, with Diana wearing a green Catherine Walker smock gown.
When William was born, Prince Charles confirmed the news to the media outside and apologised for keeping them waiting. "I was immensely relieved when it was all over," he said. "The Princess is well and the baby is looking lovely. It's marvellous, he's not bad."
Like any new parent, Kate and William will now spend time adjusting to life with a newborn baby. While they have faced the world's media, it is understandable that they would now want some time away from the spotlight.
It is thought that the Duchess will spend the much of the first few weeks of motherhood being supported by her parents, Carole and Michael Middleton, at their family home in Bucklebury.
There is also speculation that the new parents might join the Queen and Prince Philip on their annual summer holiday to the Balmoral Estate in Scotland.
The royal couple did have a few hours of peace with their new baby before the news was announced to the world.
A press release from Kensington Palace was sent out at 8.30pm on Monday evening before the official announcement was placed on an easel on the forecourt of Buckingham Palace at 8.40pm.
William and Kate's Press Secretary Ed Perkins appeared just after 8.30pm on the steps of the hospital carrying a red leather folder which he then handed over to a waiting car.
Written on Buckingham Palace notepaper, the historic document had been signed by Kate's doctors Marcus Setchell and Alan Farthing.
The document was taken under police escort to the Palace, where it was placed in a silver gilt frame before it was carried across the forecourt by a liveried footman and the Queen's press secretary, and placed on an easel just inside the central gates.
It confirmed the happy news that Britain had a new Prince.