(LONDON) -- Kate Middleton and Prince William welcomed a baby boy on Monday. The birth of the new heir was announced by Kensington Palace.
"Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 4.24 p.m.," the palace said in a statement. "The baby weighs 8 lbs. 6 oz. The Duke of Cambridge was present for the birth."
"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," the statement continued. "Her Royal Highness and her child are both doing well and will remain in hospital overnight."
The newborn is third in line to the British throne after his grandfather, Prince Charles, and father, Prince William. The reigning monarch, Queen Elizabeth II, has been on the throne 61 years. The baby is the queen's third great-grandchild.
The British Parliament is changing a 300-year-old law so that William and Kate's firstborn would be the heir to the throne regardless of gender.
Queen Elizabeth II was only person eligible to be monarch because her father had no male children.
This birth marks the first time in almost 120 years that a reigning monarch, Queen Elizabeth II, 87, is alive at the same time as three generations of heirs: Prince Charles, 64, Prince William, 31, and, now, the latest addition to the family.
The baby will someday be the monarch of 16 sovereign states and commander of the British Army, among having other royal responsibilities.
The royal couple announced the pregnancy Dec. 3, 2012, when the duchess, 31, was admitted to King Edward VII Hospital in central London with hyperemesis gravidarum, an acute morning sickness that requires supplementary hydration and nutrients.
Royal babies have typically been born within a year of marriage. Princess Diana gave birth to William 11 months after her wedding and the queen gave birth to Prince Charles six days before her first wedding anniversary.
Prince William and Kate were married April 29, 2011.
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