Kate Middleton just may be the most stylish leprechaun to ever walk this earth.

In London Friday morning, the Duke and Duchess of Cambridge marked St. Patrick's Day with a tradition that extends back more than 100 years. The royal couple attended the annual parade at Cavalry Barracks in Hounslow, where Kate presented shamrock sprigs to the Irish officers and guardsmen of the 1st Battalion.

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With Prince William dressed in full military regalia beside her, the fashionable duchess paid sartorial homage to the Irish holiday in a dark green, double-breasted coat with chic black trim and gold buttons designed by Catherine Walker. Middleton accessorized her festive look with matching green pumps, a stylish fascinator secured atop her low chignon, and a pair of gold and green onyx Monica Vinader earrings ($195;

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The duchess couldn't keep from smiling as she handed out the tiny symbols of good luck, and even bent down to say hello to the battalion's mascot, a regal Irish wolfhound.

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The royals then stopped by the Guardsman’s lunch, where members of the regiment toasted the duke and duchess and thanked Kate for the gift of shamrocks. Kate and William each celebrated with a pint of Guinness and chatted with the guards and family members: