Eddie's royal boy.
The baby, the Queen and Prince Phillip's eighth grandchild, weighed 6lb 2oz and was delivered by Caesarean section at 4.20pm at Frimley Park Hospital in Surrey.
Sophie, 42, and Edward, 43, were "absolutely thrilled". They already have a daughter, four-year-old Lady Louise Windsor.
The baby is eighth in line to the throne and is likely to be made Viscount Severn.
But he had not been named. Edward said: "You've got to get to know the small person who's just come into the world before you pick a name."