“This necklace on a chain has been worn many times before, once with a shell clam which she has since removed.”

This style of necklace appears to have been copied by other royals, including Kate Middleton.

The Duchess of Cambridge recently wore a gold pendant with the initials of Prince George, Princess Charlotte and Prince Louis.

Holding such a high sentimental value, it is no surprise Sophie has worn her initial necklace repeatedly.

Although it is unlikely Sophie would ever part with the jewel, it could fetch a huge amount of money due to its royal link.