"The Duke of Cambridge was present for the birth," according to the official Twitter feed of Clarence House. "The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall, Prince Harry & families have been told and are delighted. Her Royal Highness and her child are both doing well and will remain in hospital overnight."
"Her Royal Highness The Duchess of Cambridge has been admitted to St. Mary's Hospital, Paddington, London in the early stages of labour," the palace said in a statement early Monday. "The Duchess travelled by car from Kensington Palace to the Lindo Wing at St. Mary's Hospital with The Duke of Cambridge."
In addition to her husband Prince William, Middleton's mother and sister Pippa were also with her in the hospital, according to reports.
The child will be third in line to the British throne, behind William and William's father, Prince Charles.
A crowd of well-wishers gathered outside of Buckingham Palace, where the baby's arrival will was announced through a message brought out on an easel in public view.