The Duchess is pictured wearing the pearl pendant brooch in a portrait commissioned by her niece, Queen Victoria, in 1877.
Passed down generations of the Royal Family, the brooch was eventually given to Queen Elizabeth by her grandmother, Queen Mary, in 1953.
Her Majesty has worn the beautiful brooch on many occasions since.
For instance, in April 1976, the Queen wore the brooch with a pale blue dress for her official 50th birthday portraits.
In this new portrait, Kate can be seen wearing her emerald green dress by The Vampire’s Wife.