The Royal Family are forbidden from signing their autographs for fans for fear of them being forged or copied.
The Duchess of Cambridge is not allowed to put her signature down on paper for any fans for fear of them being copied or forged, and it would be a breach of royal protocol.
According to the Daily Express newspaper, Catherine's likely response to any requests for autographs would be: "I am Sorry, they don't allow me to do that."
Nowadays, a royal signature could fetch thousands on online auction sites.
But Prince Charles did break with royal protocol back in 2010 when he met Tony and Meg Hendy, victims of the devastating floods in Cornwall, south west England.
The Prince of Wales asked if there was anything he could do to help them and Meg replied: "Can I be really cheeky please sir and can I have your autograph for my young son Tom? I'm not sure if you do autographs but it would make his day?"
Charles then attained a piece of paper from one of his security and wrote "CHARLES 2010" on the note.
He also said sorry for his "shaky writing", and blamed it on the fact he "never writes standing up".