Image: Getty

It’s difficult to encapsulate the style of an entire era while you’re still in that era, but if we were to make an educated guess, we’d say the 2010’s will be defined by ‘ugly’ fashion. Bike shorts, child-like collars, clogs, kitten heels and corsets—our times are inspired by a ‘so bad it’s good’ approach to style, embraced by the Kardashians and Man Repeller’s Leandra Medine alike. The latest trend to add to the ever-growing list? The chunky ‘grandad vest’.

Street style pundits at Paris Fashion Week were lapping up the vest, opting for vintage-inspired styles that were layered over crisp men’s tailored shirts. They also popped up infrequently on the runway, with nods from Louis Vuitton, Etro and AMI (last season vests appeared at Givenchy and Hermès). In late September, Bella Hadid pulled off the same look for a night out in New York; last week, French It-girl Camille Charriere shared a selfie in a chunky green vest by Prada and Alexa Chung has been championing the look for months.

Image: Getty

So why the granddad vest, why now? One theory is that as shoppers have become more cognitive of the environmental impact of their clothes a new generation have began to embrace second-hand style, making the ‘pulled from the charity shop’ look cool again. Fashion editor Bay Garnett’s recent Oxfam pop-up at Selfridge’s in London showcased the growing link between thrift-store finds and high fashion. The sudden ubiquity of chunky woollen vests is perhaps evidence that the pairing can work quite nicely.

Another theory—one I’m convinced is more likely—is that Harry Styles is to thank (or blame) for all this. When he stepped out in a woollen Lanvin vest last November, in a clear homage to Princess Diana, the world collectively lost their minds. The vest—now a staple of Styles’ both on and off the red carpet—has come to symbolise the kind of geek-chic aesthetic that defines his particular brand of soft-boy masculinity. Much like Harry Styles himself, everyone wants a piece.

Image: Getty

Looking to pull off this look for yourself? Don’t be intimidated. For those in warmer climes, a sleeveless knit is actually a genius between-season investment—best worn with low-slung trousers or a good straight-legged jean. Alternatively, you can channel your inner Molly Goddard, layering a chunky Fair Isle vest over a bold, voluminous dress. Whether you prefer masculine, Scandi or totally OTT—it doesn’t matter, the internet is bursting at the seams with good options. If ever in doubt, always revert to Harry.