The Duke and Duchess of Cambridge have left hospital after the arrival of their third child.
The new prince, who was born at St Mary's Hospital, London, at 11:01 BST, weighing 8lb 7oz, is fifth in line to the throne.
Earlier Prince George and Princess Charlotte visited their younger brother at the Lindo Wing.
Kensington Palace said the Duchess of Cambridge and her son, who is yet to be named, are "both doing well".
Just before 18:00 BST, Prince William and Catherine came out of the hospital briefly to greet the crowds with their new son.
They then returned inside to collect their newborn son's car seat before driving away towards Kensington Palace.
Members of both families had been informed and were "delighted with the news".
Kensington Palace said the name of the baby would be announced in due course while a formal notice of the birth had been posted on the forecourt of Buckingham Palace.
Favourite names at the bookmakers include Arthur, Albert, Frederick, James and Philip.
Prime Minister Theresa May tweeted her "warmest congratulations" to William and Catherine.
She said: "I wish them great happiness for the future."
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