Britain is awaiting its first look at the baby boy born to Prince William and his wife, Kate.
Kensington Palace said the baby was born at 4:24 p.m. London time on July 22, weighing 3.8 kilograms.
Kate and the baby were said to both be doing well.
The infant is now third in line for the British throne after his grandfather, Prince Charles, and William.
No name was immediately announced for the child, but reports say a name is likely to be revealed soon.
The baby was born at St. Mary's Hospital, Paddington, in central London, in the same wing in which the late Princess Diana gave birth to William in 1982.
Kate, the Duchess of Cambridge, 31, and the infant stayed the night at the hospital, but were expected to leave as early as July 23.
William, who was present for the birth, was also spending the night at the hospital.
In a statement, William, the Duke of Cambridge said: "We could not be happier."
Prince Charles said in a statement that he was "overjoyed" at the birth of his first grandchild.
Prime Minister David Cameron also extended his good wishes to the royal couple.
"It's wonderful news from St. Mary's-Paddington [ hospital], and I'm sure that right across the country and indeed right across the Commonwealth, people will be celebrating and wishing the royal couple well," he said. "It is an important moment in the life of our nation, but I suppose above all it's a wonderful moment for a warm and loving couple who've got a brand new baby boy. It's been a remarkable few years for our royal family."
U.S. President Barack Obama has offered congratulations on what was described as a "joyous" event.
The U.S. statement added that "the child enters the world at a time of promise and opportunity" for the two allied countries.
Australia and Canada, two of the realms of the British Commonwealth, were also quick to extend congratulations.
Kate, who is formally called Catherine, Duchess of Cambridge, spent 10 hours in labor after she and her husband arrived at the hospital on the morning of July 22.
That evening, a written statement announcing the birth was placed upon a gilded easel outside the hospital. It prompted cheers from hundreds of onlookers and triggered the release of urgent bulletins from news agencies and television stations.
William and Kate were married in April, 2011, in a lavish spectacle that was seen by hundreds of millions viewers around the world.
The couple met in 2001 when they were students at St. Andrews University in Scotland, more than a decade ago. But their engagement to be married was not announced until 2010.
Since joining the royal family, Kate has become a worldwide fashion icon, whose dress and personal style are widely reported upon.
For decades, British royals have been treated as global celebrities, the events and scandals around their lives often generating extensive coverage on television and in the tabloids.
This phenomenon particularly intensified during the era of Diana, the mother of William and his younger brother, Prince Harry.
Diana died in a car crash in Paris in 1997, around a year after her divorce from Prince Charles was finalized.
There has been little indication of what the new baby will be named. British bookmakers have made George and James the favorites.
The British monarch is the head of state of Britain and 15 other Commonwealth countries, including Australia, Canada, Jamaica, and New Zealand.
With reporting by Reuters, AP, AFP, and dpa