The Duchess of Cambridge has safely given birth to her third child, a baby boy, this morning.
Both the baby, who weighs 8lbs 7oz, and the Duchess are 'doing well', the palace said. A name is yet to be announced.
The Duke of Cambridge was present at the birth, which took place at 11.01am, after travelling with his wife to St Mary's Hospital in central London earlier this morning.
Bookies' favourites for boys' names are Arthur, Philip and Albert. All are highly traditional royal names and it is thought the couple will not opt for a more modern option reflecting the Middleton side of the family.
The boy will share a birthday with St George's Day.
The Queen and the Duke of Edinburgh, the boy's great-grandparents, as well as Prince Charles, the Duchess of Cornwall, Prince Harry and members of both families 'have been informed and are delighted with the news', the palace said.
The Prime Minister offered her 'warmest congratulations' to the family.
"My warmest congratulations to the Duke and Duchess of Cambridge on the birth of their baby boy. I wish them great happiness for the future." - PM @theresa_may— UK Prime Minister (@10DowningStreet) 23 April 2018
The archbishop of Canterbury also gave his congratulations to the couple. 'May God bless them and all of their children with love, happiness and health,' he tweeted.
Congratulations to The Duke and Duchess of Cambridge on the safe delivery of their baby, a brother for Prince George and Princess Charlotte. May God bless them and all of their children with love, happiness and health.— Archbishop of Canterbury (@JustinWelby) 23 April 2018
The Church of England offered a prayer for the new born child.
It is highly unlikely the baby, as the third child, would ever accede to the throne. It is yet to happen in the current House of Windsor and the last time it happened was when the third child of George III and Queen Charlotte, William IV, became king and ruled from 1830 to 1837.
Under previous rules the baby prince would have leapfrogged his older sister Charlotte to become fourth in line to the throne. But the Succession to the Crown Act 2013 removed the automatic preference for male offspring, meaning royal children now inherit the throne in strict order of birth.