Catherine Middleton wore a blue Issa dress during the photocall for her engagement to Prince William of Wales on 16 November 2010, at St. James's Palace.

[5][6] In the years leading up to her engagement, the Middleton sisters wore several of Issa's silk jersey dresses to public events and formal occasions.

[11][13][14] The deep blue colour of the gown complemented the shade of the engagement ring, which had previously belonged to Diana, Princess of Wales.

[11][12] Middleton paired the wrap dress with her engagement ring, a set of sapphire cabochon earrings and a necklace, and black pumps.

"'[11] The dress, worth £385, sold out within hours of its debut in both the U.K and the U.S.[3][1][19][13] Vogue wrote that the piece became an "overnight sensation" after photos of Middleton's engagement circulated worldwide.

According to Glamour contributing style editor Tracey Lomrantz, "Women saw (Middleton's iridescent Issa dress) and thought, 'I want to look like her.

'"[30] The colour, with hues ranging "from iris to cerulean, navy to indigo and everything between", was spotted across the runways and retailers after the engagement announcement.

[31] Celebrities such as Tia Carrere, Kristen Bell, and Amy Smart were all spotted in shades of blue on the red carpet during the Spring 2011 season.