I remember the first time I saw it. It was about three years ago and my then 19-year-olds twin sons came home with some new black-and-white Adidas slides, those backless plastic sandals one might have called a scuff many fashion years ago.

I knew slides were having a cool moment. Even fashion girls were wearing them in an ironic ‘ugly’ shoe way, putting a Nike slide with a sundress. I tentatively approved.

But one day shortly after, in the style hotspot that is Westfield, my sons met me wearing the slides. With baggy black basketball shorts. And socks pulled to halfway up the shins.

“What on earth?” I shrieked. I’d been raised to think that sandals and socks were the most clueless thing on earth. They were for dags, for nerds, for tourists in canvas hats, they were un- Australian.

I mean, sure, the former fashion director of American Vogue, Grace Coddington, always wore Birkenstocks and socks to the shows, but she is in her 70s, and she’s Grace Coddington.

How could my sons publicly shame me like this outside Foot Locker on a Saturday?

“Mum, it’s fresh,” Sam said, rolling his eyes. “It’s how all the NBA guys wear them. It’s a thing.”

Pairing socks with sandals is no longer a fashion crime. Photo: Getty

And a thing it is. Looking like a Type A nerd is now the height of fashion in menswear. It’s not enough that the new cherished items are ugly on their own – the slide, the loud Hawaiian shirt, the baggy shorts, the too-short trousers.

It’s that they are worn all at once, and styled in the daggiest possible way.

Shirts are tucked in, Harry High Pants style. There is greasy hair, with side parts, geek glasses and 70s moustaches (even US talk show host Jimmy Fallon is currently sporting one). Clashing prints, floral shirts, corduroy suits.

It’s a look you once thought was the realm of the shy, socially awkward brainiac or bird twitcher but it’s probably now some skater dude who’s been dropping thousands of dollars at the Supreme store.

Italian fashion house Gucci has been extolling the look, presenting seasons of crazy gender-less mismatching that says everything about individuality, but much of the credit has to go the sports guys, the ballers, the skaters, and the hip hop crowd.

From left to right: pioneers of the nerdy look include model Bella Hadid, singer Justin Bieber and late night host Jimmy Fallon. Photos: Getty

On a recent stay at Melbourne hotel, I went down to breakfast to find myself surrounded by half a dozen very cool twenty-something young black and white guys, wearing loose basketball shorts, leopard knee socks, Nike slides, diamond earrings and baseball caps.

I knew I must have been in famous company and not wanting to blow my own dwindling cred by asking, “Where are you nice chaps from?” I phoned an insider fashion friend.

“Who’s in town?” I whispered furtively, hand over my mouth.

“Justin Bieber,” was the answer. Snap. They were clearly Bieber’s dancers. Of course.

The irony is, you can only pull off the nerd look if you’re anything but.