Duchess of Cambridge wears £29.50 Marks and Spencer trainers at SportsAid event

The Duchess of Cambridge debuted a pair of affordable M&S trainers at a SportsAid event in London. (PA)

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Following a glitzy night at the theatre on Tuesday evening, the Duchess of Cambridge dressed down as she arrived at the London Stadium on Wednesday morning to meet athletes supported by the charity SportsAid.

The duchess, who became the Patron of SportsAid in 2013, wore a previously unseen ensemble, switching her sparkling Jimmy Choo heels from the night before for trendy white trainers.

Known for her love of high street finds, the duchess’ footwear championed affordable British retailer Marks and Spencer.

The lace-up shoes with green, beige and silver stripes are available to buy for only £29.50 and are available in sizes 3 to 8 - but we’re sure they won’t be for long.

The shoes also feature Insolia Flex technology that has been approved by the UK College of Podiatrists for ultimate comfortable.

The Duchess of Cambridge showed off her sporty side at the SportsAid event. (PA)

Buy it: Ribbon Detail Lace Up Trainers | £29.50 from Marks and Spencer

The 38-year-old paired the trainers with a relaxed bottle green outfit, made up of a ribbed jumper and high-waisted trousers that are thought to be from Zara.

Keeping her look tonal, the duchess also accessorised with a pair of green onyx gemstone earrings by Monica Vinader that are available to purchase for £115.

The earrings complimented her coordinating gold necklace from Daniela Draper, which was engraved with ‘GCL’ after the duchess’ children George, Charlotte and Louis.

Throughout her visit the mum-of-three took part in a series of track activities with young athletes and chatted with British Olympian Jessica Ennis-Hill.

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