When it comes to royal fashion, Kate Middleton has an immense level of influence.
The so-called ‘Kate’ effect means that items worn by the princess regularly sell out and increase demand for vintage designs.
Since joining the Royal Family, the Princess has used this influence to attract attention to British designers.
As the saying goes: ‘If the world is watching what you wear, make it say something.’
Speaking on the Channel 5 documentary Kate: Judge My Work, Not My Clothes, fashion director Bethan Holt said: ‘Royals have always used fashion to boost their own profile and to boost the profile of the causes they want to support.
‘Princess Diana did this particularly brilliantly. She would be visiting a charity and wearing a brilliant outfit that would make the front pages the next day and automatically shine a light on those charities.’
Royal broadcaster and journalist Jennie Bond said on the programme: ‘You have to be such a diplomat if you’re going to walk the royal tightrope because you have to watch what you say at all times. And so if you can’t say it, perhaps you can wear it.’
‘Kate is incredibly thoughtful in terms of what she wears and the choices she makes,’ added designer and commentator Amanda Wakeley.
Referring to Kate’s outfit that she wore while promoting the Heads Together campaign in 2017, Wakeley said: ‘I love the way that she played down what she was wearing.
‘I think the simple crewneck sweater was her saying, “don’t focus on my clothes, focus on what we’re talking about”.’
Historian and author Dr Tessa Dunlop discussed the ‘Kate effect’ where an item worn by the Princess causes a huge influx in sales.
She said: ‘When Kate wears something, literally, those dresses fly off the peg – sometimes at the rate of one a minute.
‘You actually see the seeding of Kate as this “secret weapon” on the diplomatic stage as early as 2015.
‘That’s the first time she’s at the top table of the State Banquet. Between her and Queen Elizabeth II is the Chinese president, Mr Xi Jinping.
‘Kate very tactfully wears Chinese red. Given that Kate isn’t really allowed to say anything, that ramps up the sartorial power of her outfits. They replace her voice to an extent.
‘The wardrobe does part of her work: it always has for royals, right back to the stunning portraits of Elizabeth I in Tudor times.’
Several brands, including Reiss, Beulah London and Faithfull the Brand, have experienced significant surges in popularity following Kate’s appearances.
Maternity label Seraphine, for instance, saw a 400 per cent increase in sales after Kate was spotted wearing one of its dresses.
Years later, the ‘Kate effect’ remains as strong as ever. Her support continues to have a profound impact on brands – big and small, luxury and affordable.
Despite Kensington Palace announcing it would no longer disclose details of Kate’s outfits, they continue to sell out.
This was particularly evident on World Mental Health Day in 2023 when Kate attended an official engagement wearing the ‘Issy Star’ earrings by Scottish jewellery brand Ear Sass.
The delicate 18-carat gold-plated earrings, priced at £26, were a gift to Kate, designed as a heartfelt tribute by the brand’s founder, Sophie McGown, to her cousin Issy Phipps.
Issy tragically took her own life in April that year, and £5 from every pair sold is donated to the mental health charity Brave Mind.
Kate’s decision to wear the earrings had a profound impact. ‘Having Catherine’s support feels beyond words, especially after she wore the Issy Star earrings on World Mental Health Day.
‘To say it meant the world to us as a family would be an understatement,’ Sophie told the Daily Mail.
‘It wasn’t just that she wore the earrings – it was the way she did it, with the utmost compassion and thoughtfulness.’
The Princess’s endorsement sparked a surge in sales, raising £17,000 for Brave Mind and catapulting the brand to new heights.
Kate also uses her influence to support and uplift the British fashion industry, particularly female-led designers and brands.
Last week, the Princess of Wales visited a silk mill in Suffolk wearing a suit by the British fashion designer, Bella Freud
Sudbury Silk Mills is a family-run weaving mill that has been an integral part of the British textile industry for over 300 years.
Touchingly, the pattern also featured the Prince of Wales check, an apparent tribute to her husband, Prince William.
The clothes Kate picks out have the power to speak volumes, or allow her to fade into the background, depending on what she needs them to do.
Journalist Afua Hagan said: ‘The Princess of Wales has always been interested in charity work, right from back when she was Kate Middleton at the University of St Andrews.
‘Famously, the moment we are told William knew Catherine was “the one” was when she was participating in a charity fashion show and she was wearing that see-through dress.
‘He paid handsomely to be in the front row and apparently said “Wow, Kate’s hot!”
‘So charity work, perhaps, led her to find her prince.’
Kate also uses fashion to make bold, political statements, according to Bethan Holt.
She said in the documentary: ‘When the Princess attended the Earthshot prize with William, she had this real “wow” fashion moment where she wore this fluorescent green, strapless dress to the awards ceremony.
‘It wasn’t only green in colour, it was green in its providence as well as she had rented it through a site called Her.’
It was the first time a royal had rented a dress for an event and made a powerful message about the importance of sustainable fashion.
‘She used the soft power of fashion brilliantly,’ said Wakeley.
‘A princess wearing a rented dress is such a powerful statement.’
‘Just because people want to know about what she’s wearing doesn’t mean that they don’t want to know about what she’s doing.
‘She does incredible work while looking incredible. Surely that’s win-win,’ Amanda Wakeley aptly concluded.
Kate: Judge My Work Not My Clothes airs on Channel at 8:30pm on Saturday, September 20.