Although one of the 38-year-old's go-to designers, she famously wore the label in Prince Charles' 70th birthday portraits in November of last year, it was a daring move from the Duchess' usual attire.
With dramatic shoulder pads, balloon sleeves and delicate pleats, the look unapologetically channelled the '80s. Continuing the green theme, she stepped off the plane in a forest green Catherine Walker coat and dressed up the ensemble with a co-ordinating L.K. Bennett clutch, Emmy London pumps and her favourite Asprey London earrings.
A black velvet headband pushed the ensemble into 2020, as she gave a regal spin on one of the biggest trends of the season.
Prince William also paid sartorial tribute to the country, as he walked alongside Kate in a green polka dot tie.
The couple were greeted by Irish President Michael D. Higgins and his wife Sabina Coyne. First on the agenda was afternoon tea where they chatted over shamrock shortbread and lemon drizzle cake.
Later, the foursome attended a wreath-laying ceremony at the Garden of Remembrance.
For an evening reception at the world-famous Guinness Storehouse Gravity Bar, the Duchess of Cambridge flexed her sartorial know-how once more, as she changed into a sparkly Vampire's Wife dress.
In another sartorial shout-out to the nation, she chose deep green velvet shoes to match.