Mother and baby are said to be doing well. The Prince William was present at the birth.
The announcement of the royal birth was made via a press release sent out by Kensington Palace. The royal household made a last-minute change of plan to relay the news in this way first, rather than following royal tradition by making the announcement on an easel outside Buckingham Palace.
It remains to be seen what William and Kate decide to name their baby.
Prince Charles and Princess Diana announced Prince William's name seven days after he was born, while Prince Harry's name was confirmed the day he left hospital.
The new royal baby will carry the title of His Royal Highness Prince (name) of Cambridge.
Following the example set by William’s own parents, he and Kate are expected to present their firstborn to the world on the steps of St. Mary’s, and the official name is to be released within the next few days.
On Monday, Britain awoke to the exciting news that Kate had been admitted to St Mary's Hospital in the early stages of labour. A royal convoy was spotted arriving at the hospital's rear entrance at around 6:00 a.m., and at 7:30 a.m., London time. Kensington Palace confirmed the news the world had been waiting for.
"Her Royal Highness The Duchess of Cambridge has been admitted this morning to St Mary’s Hospital, Paddington, London in the early stages of labour," the statement read. "The Duchess travelled by car from Kensington Palace to the Lindo Wing at St Mary’s Hospital with The Duke of Cambridge."
While the baby's due date was never announced, it is thought that the little Prince was around a week overdue.
The public will now excitedly await their first glimpse of the little newborn, and his delighted parents, who are expected to proudly introduce the baby boy to the world on the steps of the Lindo wing.
Watch all the action from outside the Lindo Wing as the world awaits news of the arrival of the Prince or Princess
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