Billy the Kid? William H. Bonney. An outlaw with a baby face and a very misleading first name. Billy Crystal? William Edward Crystal. Funny guy, formal by birth.
Billy Bob Thornton? Yep, that’s William Robert Thornton. Billy Idol? William Michael Albert Broad. Even punk rockers have secret royal names.
And let’s not forget Billy Madison. That character is pure, chaotic William energy. He was a man-child, but he was our man-child.
The Royal Exception
Prince William is called “Wills” by his mates. Never “Billy.” Why? Because a future king can’t be a Billy. A Billy plays air guitar in a garage. A William signs treaties.
So, the nickname is a class marker too. It separates the pub-goers from the palace-dwellers. Fascinating, right?
What is Billy Short For? (The Definitive Origin of the Name) - blkpn.com