The Duke and Duchess of Cambridge marked their final night in Australia with a cocktail party at the home of their host, Australia Governor-General Sir Peter Cosgrove, who praised the couple for their time spent in the country.

For the celebratory occasion, Middleton wore a white dress by American designer Lela Rose, marking the event with the most formal outfit of the trip. The cocktail frock featured delicate lattice work on the sleeves and around the waist, and she styled it with simple black suede pumps and a romantic chignon updo. Since arriving Down Under three weeks ago the Duchess has not made a single fashion misstep, and on her last evening of the royal tour Middleton’s elegant look ensured she went out in style.

See More Photos: Kate Middleton’s Royal Tour Looks

Earlier in the day for a series of engagements in in Australia’s capital city, Canberra, Middleton wore a custom emerald green Catherine Walker coat dress (the same designer who created her first look on the trip). The ensemble featured a belt at the waist and full A-line skirt with hand pick stitching, which she paired with with her favorite nude L.K. Bennett pumps. The royal couple planted an English Oak tree near the Pod children’s playground, attended a reception at Parliament House hosted by Prime Minister Tony Abbott for a round of farewells, and finally stopped at the National Portrait Gallery.

Want to see all Kate Middleton’s looks from the Royal Tour? Click through our gallery to see everything she wore Down Under, plus more of her most memorable outfits ever.