The Story Behind Prince William's Amusing Military Nickname
A lot is expected of you as a member of the British royal family, and as the Head of State and Head of the Armed Services, the senior-most royals are expected to serve the British military in some capacity. During World War II, Queen Elizabeth became the first female royal to partake in active duty for the British Armed Forces, joining the Women's Auxiliary Territory Service in 1947 (via Biography). Prince Philip had an esteemed career in the British Navy, as did his eldest son Prince Charles, per Town & Country.
Despite being a more modern royal than his father and grandfather, Prince William also served in the military after graduating from the University of St Andrews in 2005 (via Forces.net). He became a British Army officer a year later and earned even more titles as he progressed through his service.
William made dozens of friends working for both the Royal Air Force and the Royal Navy. But instead of calling him by his royal titles, they came up with something else.
Prince William actually has a surname
Once Prince William started serving in the British military, he had to go by something other than his royal moniker — i.e., a first and last name. As Prince Charles is the Prince of Wales, both William and Prince Harry took the country as their surname while in the armed service. According to Marie Claire, William and Harry were given this surname when they started nursery as they were the first royals not to be home-schooled.
So while William was known as the Duke of Cambridge and His Royal Highness to the royal family and British public, to his school and military friends, he was simply William Wales. This name came to be a source of humor among his colleagues in the British army — especially when he came to be known as Flying Officer Wales in the Royal Air Force (via London Net). They soon came up with the nickname "Billy the Fish," referring to a character in the British comic "Viz."
Prince William was a big fan of his nickname
Prince William's new nickname caught on pretty quickly, and before long, even his teachers in the Royal Air Force were using it. A source told The Sun (via London Net) that William was "tickled pink with the nickname" and that he wore it as a badge of honor. "The badge is just an extra incentive for him to qualify," referring to the fact that the character Billy the Fish was a goalkeeper.
William remained close with his military friends long after they parted ways, and they came up with the ultimate prank in the run-up to his wedding. As the royal was based at RAF Valley in North Wales near the time of his wedding (via My London), William's friends decided to scatter all sorts of memorabilia of the Duke and Duchess of Cambridge around their base. "So he might open a locker and find stuff, or find his own face on a cushion or see it on a cup when you give him a cup of tea," one of his friends told Hello! magazine.