Meghan Markle, the Duchess of Sussex and wife of Britain's Prince Harry, has given birth to a baby boy weighing 3.26kg.
The baby, yet to be named, was delivered at 5.26 am local time on Monday, Buckingham Palace said.
The child, the couple's first, will be seventh-in-line to the British throne.
In a brief interview released to the media, Prince Harry said the couple were “absolutely thrilled.”
"Mother and baby are doing incredibly well,” he said. “It's been the most amazing experience I can ever possibly imagine, how any woman does what they do is beyond comprehension.”
He said the couple were “still thinking about names,” adding: “That’s the next bit. I think we'll be seeing you guys in probably two days time, as planned, as a family to be able to share it with you guys and so everyone can see the baby."
Harry added that he had been present for the birth, describing it as “absolutely incredible.”
“I'm so incredibly proud of my wife and as every father and parent would ever say, you know, your baby is absolutely amazing,” he said. “But this little thing is absolutely to die for. So I'm just over the moon.”
The baby will be the eighth great-grandchild of the 93-year-old queen, the world's longest-reigning monarch, and could be entitled to hold joint British and American citizenship according to nationality rules.
However, the child will not automatically be a prince or a princess as any such title will have to be bestowed by the queen.
The pregnancy was announced on October 15, 2018 while the couple on were a tour of Australia.