First there were bets on if the newest member of the royal family will be a girl or a boy.
As with their two other children, the royal couple did not know whether the baby was going to be a boy or a girl.
The couple introduced their little prince to the world just a few hours later, cradling him on the steps of St Mary's Hospital, London. "I wish them great happiness for the future".
Prince George's godparents are Zara Tindall, Prince William's cousin; Oliver Baker; Emilia Jardine-Paterson; Hugh Grosvenor, the seventh Duke of Westminster; Jamie Lowther-Pinkerton; The honorable Julia Samuel; and William van Cutsem.
Chicago Tribune reports that Arthur and James are among the favorites.
The birth was also to be celebrated with a 41-gun salute in London's Hyde Park, while 62 rounds were fired near the Tower of London.
And just like that, she was back at Kensington Palace.
There is no word yet on the baby's name.
NBC News' interactive below takes a look at who's who in the monarchy and the line of succession.
John Loughrey, a veteran royal-watcher who camped outside the hospital for two weeks, said the baby would be "very good for our country and of course, Her Majesty the queen".