Prince William made a rare comment about Kate's appearance during their Birmingham visit ahead of their anniversary.
They celebrated the city's diverse culture and creative industries, including a stop at an Indian restaurant.
During a walkabout, a member of the public complimented Kate's outfit, to which William responded.
Fans shared the viral video of the moment on social media.
She wore a pleated trench dress by Karen Millen, which sold out within hours of her being photographed wearing it.