Kate travelled with her husband in a car from the palace to St Mary’s Hospital in Paddington, West London, where she delivered the third in line to the throne at the hospital’s private Lindo wing.
It is the same location that both Prince William and Prince Harry were born.
Prince William was at the birth of his first son, according to an official statement from Kensington Palace.
“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,” the statement read.
“Her Royal Highness and her child are both doing well and will remain in hospital overnight.”