The Duchess of Cambridge also donned her yellow Royal Family Order on the left of her frock which she first debuted in October 2018. The prestigious honour, also worn by the Duchess of Cornwall and Princess Anne, features a miniature portrait of the Queen as a young woman surrounded by diamonds.
As though that wasn't enough to steal the spotlight, the royal accessorised the look with the Nizam of Hyderabad necklace - a piece loaned to her by the Queen. The dazzling item was first given to Her Majesty as a wedding gift in November 1947. Kate last borrowed the family heirloom in 2014 for a black tie event in London.
Even more notably was Kate's newest piece of jewellery. As pointed out by royal blogger What Kate Wore, pictures taken inside last night's event appear to show Kate wearing a new ring on her right hand. Most photos were taken from a distance, so it's difficult to make out the exact design, but the reception is thought to be the first time Kate has worn this piece. When Buckingham Palace released the details of the Duchess' outfit, it failed to mention the ring. Thus, this shall remain a mystery...perhaps a gift from Prince William?
But Princess Diana is never far from any royal gathering and the Duchess of Cambridge paid tribute to her late mother-in-law in the Cambridge Lover's Knot tiara.
The sentimental item was crafted by royal jewellers Garrard in 1914 for Queen Mary and the heirloom was later handed down to Princess Diana in 1981, as a wedding present from Queen Elizabeth II.
Kate frequently wears the sparkler to royal events and was last spotted wearing the Cambridge Lover's Knot at a state dinner during Queen Letizia and King Felipe VI of Spain's visit to Britain in 2017.
At last year's Diplomatic Corps, the Duchess of Cambridge also wore the world-famous tiara to accessorise her sky blue Jenny Packham gown.
Once again, we bow down to Kate's unstoppable wardrobe.