Before marrying into the royal family in 2011, we never saw Kate wearing a tiara in public, and this is all down to etiquette.
Grant Harrold, also known as The Royal Butler, explained that tiaras can only be worn after 6pm and are typically reserved for married women.
Grant tells Yahoo UK: “For married ladies, it was a sign of status and would show you were taken and not looking for a husband.
“For the gentleman, it was a clear sign not to make advances toward the lady in question.”
The Queen has a vast collection of jewels in the royal vaults, passed down to her from the Queen Mother and her grandmother Queen Mary.
She regularly loans pieces out to younger members of the Royal Family. Kate wore her first tiara on her wedding day on April 29, 2011 – the Cartier Halo.
Since then, she has also worn two other headpieces from the Queen’s collection, including the Lotus Flower and the Lover’s Knot.
Kate was seen in a tiara for the ninth time at the Queen’s annual Diplomatic Reception on 4 December 2018.
And it’s not just crowns, the Duchess has also borrowed earrings, bracelets, necklaces and brooches from Her Majesty.
Read more from Yahoo Style UK:
Kate wore Princess Diana’s Lover’s Knot tiara and Collingwood diamond and pearl drop earrings for the Queen’s annual Diplomatic Reception 2018. She teamed the jewels with a bespoke Jenny Packham gown and her Royal Family Order (PA)