People around the world are eagerly awaiting the first glimpse of the royal baby.
William and Kate spent the night at hospital bonding with their new son who was delivered at 4.24pm on Monday weighing 8lb 6oz.
The Duke and Duchess of Cambridge “could not be happier” at becoming parents.
The Duke was at the Duchess’s bedside when she gave birth at the Lindo Wing of St Mary’s Hospital in London.
The royal couple could leave hospital today with their son and show the baby prince to the world’s waiting media and well-wishers.
The Prince of Wales, who has become a grandfather for the first time, summed up the feelings of the Royal Family when he described the new arrival as an “incredibly special moment for William and Catherine”.
William telephoned his family to tell them the good news, speaking personally to the Queen, his father Charles and younger brother Prince Harry.
A Buckingham Palace spokesman said: “The Queen and Duke of Edinburgh are delighted at the news.”
The new royal baby is third in line to the throne. He will be the 43rd sovereign since William the Conqueror if, as expected, he follows reigns by Charles then William.
The Prince of Wales issued a brief statement saying: “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.”
William and Kate’s son is the first Prince of Cambridge to be born for more than 190 years.
The last was Prince George of Cambridge, a grandson of George III and the only son of Prince Adolphus Frederick, the 1st Duke of Cambridge.