When considering summer investments, it’s probably shorts or sunglasses that top the list. But another item is coming into the frame – the summer jacket. Once the kind of afterthought layer stashed in a bag when leaving the house and thinking about the potential chill in the air in the pub garden as the sun goes down, they have become a low-key statement item. In fact, certain light jackets – ranging from the Carhartt Michigan to The Row’s Frank jacket – are now so cult that you might not want to take them off when you reach your destination.

Some of this shift comes through celebrities. Once, most men only wore suits to award ceremonies or press engagements, but they are now just as likely to wear a statement jacket. See Mr Josh O’Connor in a buttery biker jacket on the Challengers press tour, Mr Joe Alwyn in Bottega Veneta at Cannes, Mr Jake Gyllenhaal on Good Morning America with a pinstripe blazer and jeans or Mr Ryan Reynolds in a BODE varsity jacket for the premiere of IF in New York.

Names more on the radar of fashion obsessives are also upping their jacket game; shopping at Gucci in May, former Valentino designer Mr Pierpaolo Piccioli wore a Carhartt jacket. Meanwhile Mr Jonathan Anderson took his bow at LOEWE in January wearing a vintage army jacket. It was one of those rare US Navy jackets made in a limited run decades ago and are now so sought after today that prices for it can reach more than £6,000 on eBay.

Fictional style icons are in on the act, too – see the sell-out patchwork wool NN07 jacket worn by Mr Jeremy Allen White’s Carmy in The Bear. Never one to switch his clothes up too much, it steals key scenes of the latest series as well.

Ms Ilaria Urbinati is the red-carpet stylist who put Reynolds in the BODE jacket. She is a big fan of making a summer jacket into a statement piece. “From a styling perspective, a jacket really helps make a look feel complete even in summer,” she says. “It looks more elevated than just wearing a short-sleeve shirt or polo.”

This is, of course, a principle that goes beyond celebrities at film premieres. In fact, the statement summer jacket can function as a no-brainer item in an everyday wardrobe. “You can easily throw it over your outfit for a summer evening to go out or to dinner without having to change,” Urbinati says.

Mr Dan May has been doing just that for a long time. “The jacket is the first thing I think of [getting dressed in the morning], and then what trouser and shirt to put with it,” says the former MR PORTER Style Director and co-founder of the brand SMR Days. May increasingly sees this in others’ wardrobes, too: “I think the jacket can become the feature [of an outfit], much more than it used to be.”

If low-key is more your type of feature, workwear-inspired soft jackets or chore jackets are an easy upgrade – one that French brands such as Officine Générale, A.P.C. and Hartford all excel at.

Officine Générale founder Mr Pierre Maheo says that the shape of his brand’s Leo jacket has evolved over time. “I have been working for few seasons now on more of a hybrid jacket, something between a chore jacket and traditional jacket,” he says. “The perfect mix of a chore jacket with a tailoring point of view.” Maheo nominates photographer Mr Bill Cunningham and Italian industrialist and Formula 1 icon Mr Gianni Agnelli as references.

At Hartford, the Perry jacket is a standout. The Parisian brand’s CEO Mr Yann Chareton says the appeal of these designs is that they manage to do several things at once. “I think people like the casualness of these pieces, especially during summer,” he says. “It’s a feel-good piece, but it remains a bit dressy because it’s a jacket – that’s what people really look for now.”

For many brands, the adaptability of this garment – one that can be worn as a shirt or a light jacket – is a big plus.

The Carhartt Michigan could be said to be an OG of the chore shape – and interest in it has intensified alongside that in the American workwear brand itself. Mr Alan Wright, a Carhartt collector for more than 20 years, says the look can be traced back to the first chore coat design from 1917, but brought up to date. “Carhartt is a brand that really sticks to its guns and to tradition,” he says. “So, using traditional materials and traditional colour palettes, but with some tweaks, makes a lot of sense.”

Wright says the appeal of the Michigan as a summer jacket again comes down to the ease factor. “You can put it on over a suit, or you can throw it on over a T-shirt and jeans,” he says. “It’s just easy to wear.”

Still unsure? “If you are in between two sizes, take the next size up,” Maheo advises. “You reinforce the look when it is a bit oversized.”

The casual statement jacket is an idea that has penetrated even the most rarified of spaces. “I was at a posh members’ club last night,” May says. “There were gentlemen who are obviously making lots of money, but none of them were wearing formal jackets. [Outerwear is] definitely going in a much more casual way.”

Urbinati thinks the trend will only continue. In fact, she advises to invest now. “I think it’s good to have a couple of different styles,” she says. “I love an unlined silky or linen or cotton workwear-style jacket for a chic look or a cotton bomber for something a little more youthful – different jackets for different vibes.”