We know, we know, but this really <i>is</i> the piece you need in your wardrobe this season. Plus, the men who wore the classic jacket best .

“There are three things in this world that you need,” says Henry Sagan, the homeless man played by Mr Robin Williams in the movie The Fisher King. “Respect for all kinds of life, a nice bowel movement on a regular basis and a navy blazer.” While we at MR PORTER certainly wouldn’t disagree with any part of this sentence, we can particularly endorse the lattermost element. Because the navy blazer remains one of the most stylish and versatile items in a man’s wardrobe. It’s long transcended school- and sportswear – not to mention the vicissitudes of fashion – to become a sartorial cornerstone, bridging the gap between formal and casual with peerless ease.

As the likes of actor Mr Dustin Hoffman and singer-songwriter/icon Mr Serge Gainsbourg demonstrate, the navy blazer is equally at home when dressed up with a preppy tie and chinos or dressed down with a chambray shirt and jeans – no small consideration when attempting to navigate today’s smart-casual dress codes/minefields, from offices to weddings to restaurants.

The blazer we’ve selected as our one of our Essentials comes courtesy of Italian brand Boglioli. It’s been crafted in the house’s characteristically soft style – which means relaxed shoulders, a half lining and a textured hopsack weave – to combine the polish of a tailored jacket with the easy fit of a cardigan. This is a jacket that will take you seamlessly from a casual-but-smart office look to a smart-but-casual-and-maybe-even-slightly-louche dinner or nightclub date. Nothing could more comprehensively demonstrate the navy blazer’s enduring utility, except, perhaps, the various ways in which the following men of style have embraced it.

It’s 1980, and megastardom is about to descend on the unassuming Mr Harrison Ford. The Empire Strikes Back has just been released, Raiders Of The Lost Ark is a year away and Cowboys & Aliens isn’t even a blip on his radar. How is he adjusting to his new-found fame? By elevating his American-in-Paris look to that of would-be-incognito eminence with the simple addition of a well-cut navy blazer. We like the studied insouciance of this ensemble. The navy works particularly well alongside the contrasting, grey-brown shirt. While we also like the “Han who?” expression, we don’t think he’s fooling anyone.

“Would you like me to seduce you? Is that what you’re trying to tell me?” As Benjamin Braddock in the 1967 classic The Graduate, Mr Dustin Hoffman eventually succumbs to the blandishments of Mrs Robinson, played by Ms Anne Bancroft. And who’s to say that his blazer, given some tonic verve by its mohair weave and some preppy flair with the striped rep tie, may not have played its part in her dogged pursuit? The slim cut, narrow lapels and low buttoning help to elongate Mr Hoffman’s undeniably diminutive stature, though the tumbler of Scotch can’t be discounted on the inhibition-loosening front.

“Je t’aime… Moi non plus,” growled Mr Serge Gainsbourg on his notorious heavy-breathing hit with Ms Jane Birkin in 1968, but there’s no “Nor do I” when it comes to his winning way with a blazer. This is a man for whom the word “louche” might have been coined, and we love the Gitanes-and-cognac-ready way he’s teamed this one with a simple blue shirt and a pocket square that seems to echo the pattern of Ms Birkin’s scarf. NB: while we revere Mr Gainsbourg as the ultimate flaneur, we perhaps wouldn’t advise you ape his habit of sleeping in his clothes for days on end.

We’re not sure that we’d look as serene as the late Mr Joe Frazier, pictured here in 1968, if we were about to head into the ring at Madison Square Garden to face champion heavyweight boxer Mr Buster Mathis. He was obviously cut from a different cloth from us. His blazer is not only robust enough to square up against the counter-punching of the chunky cream polo-neck and sea-green trousers, it also adds an uppercut of its own with its raffish peak lapels. A technical knockout (which indeed it was for Mr Frazier, in the 11th round).