Not only has Kate Middleton captured the heart of Prince William, now she’s caused a fashion craze across the pond.

The gorgeous would-be queen, already a noted style icon, wore a long-sleeved sapphire blue dress when she and the future King of England announced their pending nuptials on Tuesday. And now Vogue UK reports that the stunning number by Issa London, which retails at £385 (about $617) sold out at high-end British department store Harvey Nichols within 24 hours.

“Since the announcement of the royal engagement we have been inundated with requests regarding Issa,” buying director Averyl Oates told the magazine. “The dress worn by Kate sold out almost immediately. Issa is one of our best selling brands and the versatility of the pieces mean that they can be dressed down for the day and dressed up for special occasions.”