Going for the gold!

Kate Middleton stepped out Thursday to attend the National Portrait Gallery's Olympic-themed new exhibit in London wearing a stunning Stella McCartney royal blue dress and Prada pumps.

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But the real show-stopper of The Duchess of Cambridge's ensemble was the 18 karat yellow, rose and white gold diamond Trinity de Cartier necklace. The Olympics-inspired necklace features five rings and comes with the price tag of $70,500.

The Duchess' electric blue dress was also Olympics-themed as McCartney created Great Britain's Olympic team uniforms for the 2012 games. 

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Middleton, 30, attended the pre-Olympics event without husband Prince William by her side. The "Road to 2012: Aiming High" exhibit reportedly features a photo of the Duchess taken earlier this year of her playing field hockey in Olympic Park, the Daily Mail reports.

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And William's wife also has a special connection to the exhibit. She wrote her art history thesis while at St. Andrew's University -- where the couple first fell in love -- on Lewis Carroll's photography.

This article originally appeared on Usmagazine.com: Kate Middleton Wears $70,500 Necklace for Daytime Event