Duchess of Cambridge, Kate Middleton gives birth to baby boy
The baby was born at 4:24 p.m. (11:24 a.m. EST) and weighed 8 pounds, 6 ounces.
"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," Clarence House, Prince William's office, said in a statement.
The new arrival immediately changes the line of succession to the British throne, which has been occupied by the new arrival's 87-year-old great-grandmother, Queen Elizabeth II, for six decades.
No name was announced, but the new arrival will be formally known as His Royal Highness the Prince of Cambridge. The boy's name will be announced in due course, the statement said but bookmakers make George the favorite name, followed by James.
The Duchess chose to have her baby at central London's St. Mary's Hospital, where Princess Diana gave birth to Prince William and his brother, Prince Harry.
She had arrived there, in the early stages of labor, shortly before 6 a.m. on Monday.
Kate and William, both aged 31, met when they were students at St. Andrews University and were married in April 2011 in a spectacular wedding broadcast around the world.