The Duchess of Cambridge dazzled in a floor-length cream gown with thigh-high split as she attended a private dinner with her husband on Tuesday.
The royal couple were guests at an event held by the prestigious Thirty Club, whose members are some of the most powerful people in advertising and the media.
William also looked dapper in black tie as he walked down the red carpet of the event at London hotel Claridge's with his wife by his side.
Kate accessorised her outfit with diamond drop earrings, a silver clutch bag and silver vertiginous heels with open toes, meaning she had to eschew her usual opaque tights and go bare-legged.
Meanwhile her hair was in its usual style, with loose curls falling down around her shoulders.
A spokeswoman for Clarence House declined to comment on the event, saying: "It is a private engagement."
The fashionable outing comes as just last week Kate topped a poll of best-dressed royals for her understated "Best of British" style.
The Duchess came first in a survey of more than 1,000 women on website DottyBingo.com, achieving a third (33%) of the vote.