She was apparently removed from the list of 'approved celebrities' for Victoria Beckham's collection following her Twitter denial of an affair with Posh's husband, David.
But the classical welsh singer, was wearing the £1,650 cobalt blue pencil dress for Victoria's Spring/Summer 2012 collection to meet Prince Charles and the Duchess of Cornwall during a tour of a Macmillan Cancer Support unit in University College Hospital.
In an interview with the Mail Online a year ago, Katherine spoke of her love for VB's designs saying: 'What I love about Victoria Beckham dresses is that they’re simple in the lines and they do everything to emphasise the female form so it pulls you in the right places and it makes you feel very womanly. The zips are great. When you buy an expensive dress, so often the zips go on them, but hers have this double zip. She knows what us girls need!'
The fitted dress, which hugged 32-year-old Katherine's curves in all the right places, was first worn by Posh, 38, at a Vanity Fair party in Hollywood in February 2012.
Love the dress? Then get an almost exact match from online fashion retailer Mcberry.co.uk for £79.