That’s if our fingers are fast enough, of course. Within weeks of Kate’s engagement to William, the so-called ‘Kate Effect’ was born, referring to her power to make an item sell out and propel a business to new heights.

One of the earliest beneficiaries was Reiss, one of the Duchess’s favourite shops in her 20s. On the couple’s first royal tour as husband and wife to Canada in 2011, she rewore the label’s Nanette dress (first seen in their engagement portraits) for a military ceremony. And when Kate and William met Barack and Michelle Obama at Buckingham Palace the same year, she chose Reiss’s cappuccino-hued £175 Shola dress – an apt choice in which to be pictured with the First Lady who had made J Crew a White House norm.

At these moments, the Kate Effect was astonishing. ‘From a sales perspective, specifically looking back at the moments Kate wore the Nanette dress and the Shola dress, we were inundated with enquiries and interest,’ notes the brand’s founder David Reiss. ‘The immediate media attention and press coverage promoting the brand was unbelievable, so much so that both dresses sold out very quickly online.

‘With the Shola dress, the surge in web traffic caused our website to crash. And once we were back up and running, at one point we were selling one per minute until it had completely sold out. In the US it sold out before stores even opened their doors, with people calling our customer services number and buying over the phone.’

Ten years on, the Duchess’s impact hasn’t waned. There are still so many examples of her patronage making a huge difference to brands big and small, expensive and affordable.

‘In those days, we were still working from a tiny studio in the basement of my home, with just one tailor, and we were totally unprepared for the response. It was fabulous and we will forever be grateful to the Duchess. The press we received put our tiny business on a broader map which was incredibly helpful.’

The Kate Effect can be transformative. When she brought Anita Dongre to global attention in 2016 by wearing a customised version of one her traditional designs in Mumbai, the Indian designer’s website crashed from the demand. And Aisling O’Brien, founder of Irish jewellery label All the Falling Stars, has been able to give up her day job to concentrate on the brand full-time thanks to the Duchess’s support.

‘When someone like the Duchess of Cambridge wears your brand, it fills you with immense pride,’ say Francesca Kelly and Marianna Doyle, founders of Soru, one of Kate’s favourite affordable jewellery labels. ‘She opened our brand up to the international market and gave us great exposure around the globe.​ She is such an icon and always will be, it’s amazing that our small brand can be a part of that.’