Princess Kate's sell-out red shorts just proved the 'Kate effect' is back for 2026


The mother of Prince George, Princess Charlotte, and Prince Louis completed the gruelling National Three Peaks Challenge in support of The Royal Marsden Cancer Charity last week


Kate Middleton, the Princess of Wales visits the Piazza Camillo Prampolini where she is welcomed to the city at Reggio Emilia’s Town Hall during the first day of her visit to Reggio Emilia on May 13, 2026 in Reggio Emilia, Italy. © Samir Hussein/WireImage
Laura Sutcliffe
Laura SutcliffeFashion and Beauty News Editor
1 hour ago
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It's been just over a week since the Princess of Wales was the ultimate action girl as she nailed the Three Peaks challenge with major aplomb.

The royal mother of three climbed the UK's three highest mountains – Ben Nevis in Scotland, Scafell Pike in England, and Yr Wyddfa (Snowdon) in Wales – over the course of 24 hours.

Incredibly, Kate did this challenge alone, with support along the route from Mountain Rescue, and was greeted at the bottom of Yr Wyddfa by her husband, Prince William, and her three wonderful children, Prince George, Princess Charlotte and Prince Louis. Her parents, Carole and Michael Middleton, and her brother James also cheered her on.

In one photo, Kate hugged her daughter, Princess Charlotte, 11, as Louis, eight, could be seen throwing his hands in the air© Instagram
Kate looked incredible post hike

On Sunday, Kate took to her official social media platform to reflect on the milestone event, sharing a selection of heartwarming images of herself meeting her emotional and proud family at the bottom of Yr Wyddfa.

Kate Middleton reunites with members of her family after completing the National Three Peaks Challenge© The Prince and Princess of Wales
The royal wore a sleek pair of shorts by North Face

Looking gorgeous despite the tremendous journey she had undertaken, Kate showcased her long, athletic legs in a pair of £65 North Face Summit Series Pacesetter shorts in the colour 'iron clay'. A new item in Kate's wardrobe, they are durable, lightweight, breathable and water-repellent - ideal hiking attire. Since Kate stepped out in them, they have almost sold out in the striking burnt orange colourway.

The Kate effect

As Kate has grown older, she doesn't seem to purchase as many high street items, or even current items from designer brands. Her fashion focus appears to be bespoke pieces, crafted exclusively for her by fashion houses. So when she does wear something off the peg, it nearly always flies off the shelves.

The couple got engaged in 2010© Chris Jackson/Getty Images
Kate caused a sellout situation in 2010

The phrase 'the Kate effect' was coined in 2010, when the royal wowed in an ISSA blue wrap dress to announce her engagement to Prince William. The silk-jersey wrap dress sent royal fans into a frenzy, with the classy fit a must-have for royal style stealers.

William and Catherine got engaged in 2010© Getty Images
Kate's ISSA dress was a huge hit for the brand

The appearance led to an unexpected spike in demand, and within hours of Kate's appearance, the dress was completely sold out. All designs by the brand were sold out shortly after the increased publicity, with ISSA unable to meet the demand and closing shop.

Speaking to the Daily Mail in 2016, ISSA founder Daniella Helayel explained: "ISSA was a niche brand; we had a loyal following, but in 2008 and 2009, we were in serious financial trouble. When Kate wore that dress, everything changed. From the day of the royal engagement, our sales doubled. I didn’t have the money to finance production on that scale."

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