COS's £35 Clean Cut T-Shirt is already a cult basic, but its new royal-purple shade has become an unexpected fashion-week favourite.

If there's one colour winning fashion week street style right now, it's royal purple . Yes, the hue once associated with royalty—and, of course, Daphne Blake from Scooby-Doo —has officially emerged as one of the season's most unexpected colour trends. And there's one piece in that exact shade that stylish women can't seem to stop wearing this fashion week: COS's £35 Clean Cut Long-Sleeved T-Shirt .

Already a perennial bestseller, the COS tee has earned something of a cult following as the ultimate elevated basic. With its structured silhouette, heavyweight cotton and perfectly boxy fit, it's the kind of simple piece that makes an outfit look instantly more considered. And whilst it's available in an array of classic shades, from crisp white to rich chocolate brown, it's the punchy royal-purple iteration that's suddenly everywhere.

On the streets of fashion week, I've spotted the saturated shade paired with everything from chocolate brown and fiery red to unexpected flashes of yellow, proving it's far more versatile than you might initially think. Wear it with brown denim for an easy autumn look, contrast it with a bright yellow skirt or let it do all the talking alongside your favourite black trousers.

Keep scrolling to shop the £35 COS tee taking over fashion week street style right now.

The rich purple tee that's everywhere right now. Pair with brown trousers for a decidedly autumn 2026 look.

This will work so hard in your wardrobe this transitional period.

The red tee is immediately statement-making.

For when the temperatures start to drop dramatically, opt for this funnel-neck cashmere knit.

Layer under black or brown knits for a delicious colour combo.

Marina Avraam is Senior Shopping Editor at Who What Wear UK , where she expertly navigates Zara, H&M, Toteme and Net-a-Porter (to name but a few) on a daily basis to unearth the most worthwhile pieces, while valiantly resisting the urge to add every single one to her basket. At Who What Wear , Marina is committed to curating a shopping experience that feels both aspirational and intentional, guiding readers to items—both affordable and investment—that will genuinely benefit their wardrobes.