Thousands of well-wishers descended on Buckingham Palace on Monday night to celebrate the birth of the Duke and Duchess of Cambridge’s baby boy.
Many tried to glimpse a formal bulletin announcing the 16:24 BST delivery of the baby, who weighed 8lb 6oz.
The birth will be marked later with a series of gun salutes and the ringing of Westminster Abbey’s bells.
Prince William said the couple “could not be happier”. Kensington Palace said the baby would be named in due course.
The duke stayed with Catherine and the new arrival – the third in line to the throne – overnight at the private Lindo Wing of St Mary’s Hospital, west London.
BBC royal correspondent Peter Hunt said it was unclear how long the baby would be kept in.