Prince William's close friend, British oarsman Oliver Hicks, has welcomed the "great and happy news" of the arrival of his son.
A statement said: 'What great and happy news to hear the baby has arrived safe and well and Kate's well too. My thoughts are with them all on this momentous day.
"I wish them all good fortune for the future. I'm delighted to be back from the sea to hear the news!."
The royal baby appeared to wave as he was introduced to the crowds outside the hospital for the first time.
The Duke and Duchess of Cambridge proudly showed the world their baby son, a future king, before taking him home tonight.