Kate Middleton, 36, joined her husband Prince William, 36, along with the Queen and Prince Philip.
The British Royal Family put on the state banquet at Buckingham Palace for King Willem-Alexander and Queen Maxima of the Netherlands.
The Duchess of Cambridge opted to wear the Cambridge Lovers Knot Tiara, which was previously owned by Princess Diana.
It isn’t the first time she has opted for the particular tiara, as she often opts for the jewelled crown at diplomatic events.
She previously wore it to a state banquet in 2017 to welcome a Spanish state visit, as well as to the annual winter party at Buckingham Palace the same year.
The Duchess of Cambridge chose an elegant Alexander Mcqueen gown for the event.
Her blue dress flattered her trim figure, with thick straps and figure-hugging bodice. The dress flared at her thighs and its long train followed behind her.
Her dress designer is also favoured by the royal – not only does she often choose the brand for events but they also designed her wedding dress in 2010.
She completed the look teardrop pearl earrings as well as a diamond and pearl necklace which was once worn by the Queen Mother.
Kate Middleton greeted Queen Maxima during her visit to the UK, who has put on a number of stunning fashionable display
The royal from the Netherlands chose an Emilia Wickstead dress which featured a sheer floor-length cape.
The embellished sequin dress was strapless with a number of jewelled adornments taking the focus of the gown. She added a jewelled clutch and the Stuart Tiara.
It features the Stuart diamond, which once belonged to King William II and Queen Mary II.
The gem was returned to the House of Orange in the Netherlands in 1702 and now sits in the bold crown.
Earlier today, the Dutch royal greeted the Queen on her first day of the state visit.
Queen Maxima chose a pink coat dress and bold matching headband for her first look in the UK.
She is currently in the UK for two days, her first as Queen since King Willem-Alexander’s mother abdicated in 2013.
The royal she was taken to experience the Picture Gallery at Buckingham Palace with a number of royal items relation got the Netherlands.
With her husband, she laid a wreath at the Grave of the Unknown Warrior and was given a short tour of the Abbey.