The mother-of-three's blue cape jacket looked similar to ones worn by the young witches of Beauxbatons, the French magic school in the Harry Potter book and film series.
Fans were quick to jump on social media to share side-by-side shots of Kate and Fleur today, writing: "Kate is one of us!" and "who wore it better?"
During this tour, the 37-year-old admitted she’s feeling “broody” as she met an adorable baby.
Kate couldn’t resist going up to five-month-old James Barr, telling his dad: “He’s gorgeous. It makes me feel broody.”