25/10/2018 5:03 AM AEDT | Updated 10/11/2018 1:55 AM AEDT

Kate Middleton Looks Every Inch A Princess In Diana's Favorite Tiara

The Duchess of Cambridge was stunning in an Alexander McQueen gown.

The Duke and Duchess of Cambridge stepped out together for a state banquet in honor of King Willem-Alexander and Queen Maxima of the Netherlands at Buckingham Palace on Tuesday.  

“These visits, both outward and incoming, play an integral role in strengthening Britain’s relationships with countries across the world,” the royal family said in a statement its Instagram account. 

For the elegant occasion, Prince William donned a tux, while the former Kate Middleton wore a stunning Alexander McQueen gown with the Lover’s Knot tiara. McQueen is one of the duchesses’ go-to designers. 

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The Duchess of Cambridge during the state visit by King Willem-Alexander and Queen Maxima of the Netherlands, at Buckingham Palace, London.
JOHN STILLWELL via Getty Images
Catherine, Duchess of Cambridge, walks with Rear Admiral Ludger Brummelaar (R) as they attend a state banquet in honor of King Willem-Alexander and Queen Maxima of the Netherlands at Buckingham Palace in London on Oct. 23.
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A closer look at William's outfit and Duchess Kate's jewels. 

The tiara is over a century old, and was a favorite of the late Princess Diana. 

Tim Graham for GETTY IMAGES
Princess Diana wears her favorite tiara in Hong Kong in 1989.

The duchess has worn the tiara on several other occasions, including diplomatic receptions at Buckingham Palace in 2015 and 2016, and a state banquet in honor of King Felipe and Queen Letizia of Spain 2017, according to Harper’s Bazaar. 

Elsewhere in Fiji, Prince Harry and Meghan Markle also wore formal attire for a state dinner on the very same day. The Duchess of Sussex dazzled in $1,430 blue, caped dress by Safiyaa, while Harry wore a tux: 

Prince Harry and Meghan, the Duchess of Sussex, arrive for a reception and state dinner at the Grand Pacific Hotel in Suva, Fiji, on Oct. 23.
A shot of the duchesses' caped dress. 

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