Kensington Palace have announced that the royal baby is here - and revealed that it's a boy!
They wrote on Twitter: "Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 1101hrs.
"The baby weighs 8lbs 7oz.
"The Duke of Cambridge was present for the birth.
"Her Royal Highness and her child are both doing well".
They added: "The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall, Prince Harry and members of both families have been informed and are delighted with the news."