Photographers remain camped outside the hospital where Kate Middleton will deliver. It's the same wing where Princess Diana gave birth to Prince William.
The father-to-be burned off some of his nervousness by playing polo at a charity event with brother Harry.
The royal baby will be third in line to the throne, behind Prince Charles and Prince William.
"There is no possibility that Prince Charles will be passed over, nor should he be passed over," royal historian Hugo Vickers said. "He will come to the throne in the fullness of time, better experienced than any of his predecessors, certainly including the present Queen, who was very young at the time she came to the throne."
The royal baby will be celebrated with two separate but simultaneous gun salutes, including a 62-round salute at the Tower of London.