Kate Moss has done it for years. Recently, the Duchess of Cambridge has been doing it too. Yet only very few women possess that particular combination of public profile and personal style that inspires other women to buy their clothes.
IN PICS: Fashion's big sellers
Trying to work out which women truly have that knack is tricky. When trumpeting a sudden rush of purchases of an item worn by a well-known somebody, companies will only describe sales increases in impressive-sounding percentages rather than potentially measly units sold. There is so much hoo-ha about the Duchess that at least some of it (see below) must be trumped up.
But for some designers a piece from their collection on the right person really can make a difference. Rupert Sanderson, the shoe designer, is still basking in the new business generated by the Duchess when she wore his grey suede Malone courts this month. He said: "The wonderful thing is that whatever these very special women wear, we sell out of."
The Duchess of Cambridge: The Phenomemon
She pops into Topshop and queues for her purchases, she buys her clothes in the sales (or even at Bicester Village) and, this week, she appeared to have borrowed the same blue Trina Reiss dress her mother first wore two years ago. Furthermore, her taste is classical, demure - and supremely safe. Yet to the chagrin of some in fashion, The Duchess of Cambridge has in the last year often proved to be genuine consumer catnip. Items that have sold out within days of her being photographed wearing them include a £325 jacquard Orla Kiely print dress in which she visited a primary school in Oxford, and a £69.99 Zara dress worn to the Royal Albert Hall last December.
Yet the side-effect of "The Kate Effect" is that some retailers cheekily attempt to co-opt it for themselves.
Last year, after the Duchess wore a Burberry trenchcoat (that model sold out nationwide within 24 hours) on a visit to Belfast, Asda informed the world that sales of a similar, £22 design in its George range had since tripled. The pictures last week of the Duchess playing hockey with the Team GB squad in a pair of coral-toned skinny jeans prompted a speedy release - from Asda again - claiming a resulting 88 per cent spike in its sales of similar trousers just a day later. Hmmm.
Sales rating: 4/5
