Prince Harry and his wife Meghan, the Duchess of Sussex, are the proud parents of a new baby boy.
The baby, who has not yet been named, is seventh-in-line for the British throne and is Queen Elizabeth II's eighth great-grandchild.
It is the first child for Harry and Meghan, who married a year ago. Harry spoke before cameras on Monday afternoon, saying they were "absolutely thrilled" as he thanked the public for their support during the pregnancy.
He said Meghan and the baby were doing "incredibly well," adding that they were still thinking about names for the infant, who was delivered at 05:26 BST.
Buckingham Palace said the baby weighed 7lbs 3oz (3.2kg), and that the duke was present for the birth.
The duchess is a 37-year-old retired US actress formerly known as Meghan Markle. The 34-year-old prince is the son of Prince Charles — next in line for the throne — and Princess Diana, who died in a Paris car crash in 1997.
Harry has long spoken of his desire to start a family.
"The Duchess went into labour in the early hours of this morning," Buckingham Palace announced this morning in a statement.
"The Duke of Sussex was by her royal highness' side. An announcement will be made soon," the palace added.
Prince Harry and Meghan revealed they were expecting their first baby in October, at the outset of a 16-day tour of Australia, New Zealand, Fiji and Tonga.
Commentators at the time believed the baby was due in late April.
The 34-year-old prince and Meghan, 37, have reportedly opted for a home birth at their new Frogmore Cottage residence, on the grounds of Windsor Castle west of London.
But it is unclear whether the first baby of the Duchess of Sussex, who is believed to be a week overdue, was delivered at home.
The move would break with the tradition followed by Prince Harry's brother William and his wife Kate, whose three children were all born in the private wing of St Mary's Hospital in London.
Buckingham Palace also said last month Prince Harry and Meghan wanted to keep the arrival of their first child "private."
That would also contrast with Prince William and Kate, whose newborns were immediately shown off by the couple in front of the world's media.
They have three children: five-year-old Prince George, Princess Charlotte, 4, and one-year-old Prince Louis.
As April came to an end without news of the birth, Britons have been on tenterhooks with royal-watchers eagerly awaiting the latest addition to the family.
Fans have already been seen gathering in Windsor as news that Meghan had gone into labour broke on Monday lunchtime.
There has been fevered speculation in recent weeks over everything from the newborn's gender and name – to whether it will have Harry's ginger hair.
Punters have been betting heavily on the various options, with the favoured scenario that the baby will be a girl called Diana.
Other hotly tipped names included Ivy, Grace and Alice.
Some British bookmakers stopped taking bets last week on when the baby would be born, believing that it had already secretly arrived.
Meghan was a popular US actress before marrying Prince Harry last May at Windsor Castle. She has been hailed as a breath of fresh air in a stuffy institution, yet she has been heavily targeted for criticism by sections of the British media.
Meghan, who grew up in California and is a long-time advocate of holistic treatments, has reportedly raised eyebrows during her pregnancy with some of her new-age ideals and US glitz.
How she intends to bring up the baby will only increase the scrutiny.
Speaking after the birth, Harry added the child had been "a little overdue" and that he planned to make another announcement in two days' time "so everyone can see the baby".
Asked what it was like to be present for the birth, he laughed and said: "I haven't been at many births. This is definitely my first birth. It was amazing, absolutely incredible, and, as I said, I'm so incredibly proud of my wife.
"As every father and parent will ever say, you know, your baby is absolutely amazing, but this little thing is absolutely to-die-for, so I'm just over the moon."
He added: "It's been the most amazing experience I could ever have possibly imagined.
"How any woman does what they do is beyond comprehension."