It’s a boy.
Prince William and Kate Middleton became parents of an 8 lb. 6 ounce baby boy late Monday afternoon.
Several hours later, William issued a brief statement saying, "we could not be happier."
Both mother and child were reported doing well and will remain in the hospital overnight.
Prince William was present for the birth at 4:24 p.m., according to a press release from the royal household.
The release also said the name of the baby, the couple’s first, would be announced “in due course.” That could be a while: it took a week to learn William's name and a month to learn Charles'.
The baby will be third in line to the throne after his grandfather, Prince Charles, and his father.
Prince Charles issued a statement Monday night saying, "Both my wife and I are overjoyed at the arrival of my first grandchild. It is an incredibly special moment for William and Catherine and we are so thrilled for them on the birth of their baby boy.
"Grandparenthood is a unique moment in anyone's life, as countless kind people have told me in recent months, so I am enormously proud and happy to be a grandfather for the first time and we are eagerly looking forward to seeing the baby in the near future."
Crowds massed outside Buckingham Palace where a formal announcement of the baby’s birth was posted to cheers Monday night.
The Duke and Duchess of Cambridge arrived at St. Mary’s Hospital – where William and his brother Harry also were born – early Monday morning.
It was not immediately clear how long labor lasted or whether the child was delivered by natural birth or caesarian section.
Representatives of the world's press had been gathered for days outside of St. Mary's Hospital.