It was one of the Queen Mother's favourite pieces, with the royal photographed wearing it on numerous occasions.
Take a look through her impressive collection below.
Meghan wore a Blue "Gingko" Cape Dress by British label Safiyaa, while Kate wore a pale blue dress by Alexander McQueen.
Princess Diana and Kate Middleton pictured wearing the Cambridge Lover's Knot tiara. Online, the tiara is more than 100 years old and belongs to Queen Elizabeth, although it was originally commissioned in 1914 for the queen's grandmother, Queen Mary.
In her will Queen Mary left the tiara to to the Queen who wore it frequently, including at an evening event in 1955.
The state banquet for the Dutch royals, the first for Willem-Alexander and his Argentine-born wife Maxima, followed the usual pattern for royal state visits, including an elaborate ceremonial welcome and a state carriage procession to the palace. It was one of her most important marital presents, coming from her groom himself, and she wore it on their wedding day at St. George's Chapel, Windsor. Prince Charles, the Prince of Wales and Camilla, the Duchess of Cornwall were also on hand for the banquet for 150 guests.
It was also seen on Kate at last year's Diplomatic Reception.