How do you celebrate St. Patrick's Day if you're the second-in-line to the British throne?

For Prince William and Duchess Kate, you celebrate not with a pint of Guinness but with an act of public service.

Prince George Takes Center Stage on William and Kate's Overseas Tour

The Duke and Duchess of Cambridge, as they are formally known, stepped out together today at the Irish Guards' annual St. Patrick's Day Parade in Aldershot, Hampshire.

Making their first public engagement together this year, William, 31, and Kate, 32, were joined by bagpipers and even a four-legged friend, the Irish Wolfhound regimental mascot, Domhnall, as they fulfilled their royal duties of serving as Colonel of the Regiment - for him - and presenting traditional sprigs of shamrock to officers and guardsmen at the base - for her.

Inside Kate Middleton's New Role - Godmother!

The royal couple appeared tanned and relaxed after their week-long vacation in the Maldives, but did not appear with their infant son, Prince George.

Kate stood out in an emerald green Hobbs coat and Gina Foster hat, a departure from the same green, Emilia Wickstead dress coat she had recycled the past two years at the same event, the U.K.'s Mirror reports.

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It was at this same St. Patrick's Day event last year that Kate, then pregnant with George, got her high heel stuck in a grate, requiring an assist from officers and her husband to set her free.