Kate Middleton showed she can do more than work a Main Street look when she arrived in a show-stopping designer gown London hotel Claridge's on the arm of Prince William last night, to attend an exclusive Thirty Club dinner.
The Thirty Club sees advertising kingpins meet for the evening - and last night Prince William was their guest speaker.
The dress, by Roland Mouret, came complete with a surprisingly daring thigh-high split.
And even shoe designer Nicolas Kirkwood would have been happy with her footwear - she slipped on a pair of very gorgeous £450 Jimmy Choo sandals.
Clarence House said the engagement was private, and declined to elaborate on the subject of William's speech.