Kate looked elegant in a white cocktail dress by Lela Rose. The white circle lace trim dress, which retails at £869, features a graphic effect to the sleeves and peplum waist over a beautifully fitted sheath dress. The Duchess competed her outfit with a black clutch bag and matching heels, and wore her hair up in a chic updo.
It's thought to be the first time that Kate was worn a creation by Dallas-born Lela who first garnered attention when she designed the outfits worn by Jenna and Barbara Bush at their father’s presidential inauguration.
Her other well-known clients include Jessica Simpson, Mary-Kate and Ashley Olsen and Selma Blair - although her new royal endorsement is likely to have a huge effect on her profile.
William and Kate were the guests of honour at the special black tie reception hosted by Australia's Governor-General Peter Cosgrove at her official residence, commonly known as Yarralumla.
It is not the first time that the residence has hosted British royalty; the Queen and other foreign heads of state stay at Government House when on official visits to Canberra.