Over the years, Kate Middleton has undeniably established herself as a style icon.

Her fashion selections reportedly contribute an astounding £1 billion annually to the economy, as noted by The Times, a phenomenon known as the 'Kate effect'.

Following her cancer treatment last year, the Princess of Wales has been making a steady comeback to public engagements. She recently released a heartfelt video for Mental Health Awareness Week and accompanied Prince William to the VE Day 80: A Celebration To Remember concert last week.

Her latest public appearance outfit has caused quite a stir online.

Kate Middleton has sparked a frenzy with the Victoria Beckham suit she wore to a recent public appearance (Ilyas Tayfun Salci/Anadolu via Getty Images)

Yesterday (13 May), Kate attended a fashion industry event to present the Queen Elizabeth II prize for British Design, wearing an olive-green trouser suit designed by former Spice Girl-turned-fashion designer, Victoria Beckham.

The suit, priced at £1,340, featured the designer's trademark 'puddling hems', or ultra-long trouser legs, and predictably sold out after the princess was seen wearing it.

Post-event, an X user posted a screenshot of the jacket's product page from the Victoria Beckham website.

"The Kate Effect. SOLD OUT," the caption read alongside the image.

Fans went wild for the £1,340 suit (Aaron Chown - WPA Pool/Getty Images)

Others took to social media to commend the 43-year-old's outfit.

One individual remarked: "The Princess of Wales looked fantastic today."

Another commented: "Princess Catherine looks amazing. She deserves a Style Award for being a fashion icon."

A third added: "Catherine is so beautiful and truly enhances British fashion."

At the time of writing, it seems the suit jacket has been restocked in a few sizes.

This isn't the first instance where Kate's fashion choices have caused a buzz.

Since joining the royal family in 2011, high-street replicas of the Princess' royal attire have flown off the shelves.

Kate has previously caused numerous items to sell out in something known as the 'Kate effect' (Arthur Edwards-Pool/Getty Images)

The Reiss 'Nanette' dress she donned during her inaugural royal tour sold out within minutes and is still being auctioned on eBay for twice its original price.

Moreover, after she wore a pair of Alicia Camilla Elphick pumps at a 2022 charity polo match, the designer revealed that 'the phones didn't stop ringing all day' and the shoes 'completely sold out'.

Recently, her husband has also influenced fashion trends, with people emulating his rugged new appearance in what is referred to as the 'Prince William effect'.

The future King unveiled a shabby-chic look last summer, which fans found surprisingly fitting, leading to disappointment when he later changed it.

At the time, aesthetics clinic owner Murat Alsac told the Express: "People are bringing in pictures of Prince William on their phones and saying, 'Make me look like that'.

"They perceive it as rugged and masculine."