The Duchess 'recycled' the off-white number from a black tie dinner last May.
Get her red carpet look for less with HELLO! Online's high street finds by clicking on the photo below.
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It wasn't just the 31-year-old fashionista's gown that got her style watchers talking.
Her dazzling statement necklace from Zara, priced at £19.99, caused a stir too. The item has sold out online but we've found two similar sparkly numbers as pictured below.