Meghan, the Duchess of Sussex, has given birth to a boy, her husband Prince Harry announced in a statement to television cameras on Monday, adding that mother and baby were "doing incredibly well".
"I am very excited to announce that Meghan and myself had a little boy early this morning -- a very healthy boy," a beaming Harry told reporters in Windsor.
"Mother and baby are doing incredibly well. It's been the most amazing experience I can ever possibly imagine."
Buckingham Palace said the boy, seventh in line to the throne, was born at 0526 local time (0426 GMT), weighing seven pounds and three ounces.
"The Duchess's mother, Doria Ragland, who is overjoyed by the arrival of her first grandchild, is with Their Royal Highnesses at Frogmore Cottage," it added.
It added that Prince Harry was present for the birth.
"How any woman can do what they do is beyond comprehension," Prince Harry said in his brief comments.
"We're both absolutely thrilled and so grateful for all the love and support from everybody out there."
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, Queen Elizabeth II's eighth great-grandchild, was due in late April.
The 34-year-old prince and Meghan, 37, reportedly opted for a home birth at their new Frogmore Cottage residence, on the grounds of Windsor Castle west of London.
The move breaks 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 also contrasted with 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.
The prince said the couple were still thinking about names.
"The baby's a little bit overdue so we've had a little bit of time to think about it," he added. "That's the next bit."
Some British bookmakers had 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
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.
London, United Kingdom | AFP