Prince William's wife Kate on Monday gave birth to a baby boy who will one day inherit the British throne, Kensington Palace said in a statement.
"Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 4:24pm (local time)," said the statement. "The baby weighs 3.8kg.
Kate and her child were both "doing well" and will remain in the hospital overnight, it added.
William was present for the birth at St. Mary's Hospital in central London while the queen was "delighted" after hearing of the news, said the 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," added the palace press release.
Crowds cheered outside Buckingham Palace as the long-awaited news was finally announced at 8:30pm.
The baby's birth was officially announced on a golden easel at the gates of Buckingham Palace, along with announcements on the Royal Family's website and Twitter page.
But it could be a while before the all-important name is announced.
When William was born in 1982, his name was not revealed for a week – and when his father Prince Charles, the heir to the throne, was born in 1948, the suspense lasted an entire month.
As is the custom in many British families, William and Kate are expected to give a nod to close relatives when choosing a name for their baby.
During Kate's pregnancy, British bookmakers have been doing a roaring trade in bets on the baby's name, with Alexandra emerging as the favourite girl's name, and George for a boy.
