The Duchess of Cambridge, née Kate Middleton, was the picture of elegance in a white-and-navy dress from the Jaeger sale for an official engagement on Tuesday.
The chic number is currently being sold on the Jaeger website for the discounted price of £99, down from £150.
When it was identified, the white dress with navy trim detail was available in several sizes, but minutes later had completely sold out.
Kate was elegant in the monochrome number
The brunette beauty teamed it with navy courts and a clutch bag in the same shade. She topped off the look with her glossy mane styled into her signature cascading curls.
Kate was out to lend her support launch of a bid to find a British team to take part in the America's Cup, the world's oldest sailing competition.
She was meeting crew and boat designers during a breakfast reception at the National Maritime Museum in Greenwich.
The royal topped off the look with her signature cascading curls
The outing marked her first solo engagement since she and Prince William returned from their tour of New Zealand and Australia.
She has, however, attended several official duties since then. Last week, she took part in the commemoration of the 70th anniversary of D-Day.
The couple also visited a whisky distillery in Scotland earlier this month.