The Duke and Duchess of Cambridge have left hospital with their baby in a car driven by Prince William himself.
The Duke of Cambridge took questions as he stood outside the hospital holding his new son.
"He's got a big pair of lungs on him, that's for sure," said Prince William.
"We're still working on name."
It's an event that's sparked celebrations round the world but right here in the East region we've more reason than most to mark the birth of the new royal baby.
There's been particular delight in Cambridge, which has a new Prince.
Those who have met the Duke and Duchess say they'll make excellent parents
In a statement issued on their behalf, the Duke and Duchess of Cambridge have thanked hospital staff that helped care for them during the birth of their son.
– The Duke and Duchess of Cambridge
We would like to thank the staff at the Lindo Wing and the whole hospital for the tremendous care the three of us have received.
We know it has been a very busy period for the hospital and we would like to thank everyone - staff, patients and visitors - for their understanding during this time.
Prince Charles has entered the Lindo Wing of St Mary's Hospital where his first grandchild was born yesterday.
His wife, Camilla, accompanied him.
"Have you had a long wait?" Charles asked reporters.
Bookmakers have seen George and James become the favourites for the new prince's name.
George was the favourite with William Hill (5/2) and Paddy Power (6/4), while Ladbrokes had James at 2/1.
Henry, the given name of the Duke's brother Prince Harry, is also in the running, along with Alexander and Louis.
Ladbrokes has Henry at 5/1, the same as it is offering George, after what it said was an "unprecedented amount of bets" in the last 48 hours bringing it in from 50/1.
The public may have to wait to cash in their betting slips. It is not uncommon for royals to take their time naming babies: Queen Elizabeth II and her husband Prince Philip waited for a month in the case of Prince Charles.
– The Prince of Wales
Both my wife and I are overjoyed at the arrival of my first grandchild. It is an incredibly special moment for William and Catherine and we are so thrilled for them on the birth of their baby boy.
Grandparenthood is a unique moment in anyone’s life, as countless kind people have told me in recent months, so I am enormously proud and happy to be a grandfather for the first time and we are eagerly looking forward to seeing the baby in the near future.
The Duke of Cambridge's uncle, Earl Spencer, described his joy at the new royal baby.
"We're all so pleased: it's wonderful news," he said.
The Earl, whose sister was the Duke's mother, Diana, Princess of Wales, added: "My father always told us how Diana was born on just such a blisteringly hot day, at Sandringham, in July 1961. It's another very happy summer's day, half a century on."