William is the son of Prince Charles and the late Princess Diana, and the grandson of Queen Elizabeth II. His wife Kate is due to give birth to their baby next month in the same wing at St. Mary's Hospital where William was born.
The couple are waiting until the baby is born to learn their child's gender.
The official birth announcement will be posted on a board outside of Buckingham Palace after the royal family has been notified, CNN said.
Swim Week Miami Beach 2014 [PHOTOS]