The daring green three-quarter length frock, which features softly gathered ruffles at the hem and sleeves and retails for about $3,000 (AUD), showed off Kate’s slender figure.
Beatrice previously donned the frock for pop star Ellie Goulding’s wedding last year, which she attended with her fiancé Edoardo Mapelli Mozzi, whom she is set to marry in May.
While Kate’s choice to wear the green gown was obviously a sweet gesture for the people of the Emerald Isle, it’s also a show of respect for her relative Bea.
The subtle nod is also a rarity for Kate as she is generally not inclined to take fashion inspiration from anyone let alone her royal relatives – and she’s never borrowed a dress from Eugenie.
The Duke and Duchess of Cambridge were attending the reception at the Guinness Storehouse's Gravity Bar, which was hosted by the British Ambassador to Ireland.
Aside from wearing the striking frock, Duchess Kate's behaviour at the evening soiree also caught the eye of royal watchers.
Kate and Wills were poured a pint of Guinness, and while William took a generous gulp, his wife was accused of taking a “fake sip”.