If you're not familiar with menswear's latest hybrid word - Athleisure - then it's time to familiarise yourself, because try as you might, you're going to be seeing a lot more of it over the coming months. Menswear's lines of division between smart and casual have become blurred and the result is equal parts stylish and comfortable - so needless to say, we're wholehearted supporters. Find out what it means for your wardrobe and why you should welcome it warmly.

Oliver Cheshire wears the Jupiter blue zip jacket

May 16th, 2016, Cannes, France. So far, so normal (well as normal as having a horde of the world's most famous descend on a Southern French town gets). Then Oliver Cheshire steps out with girlfriend Pixie Lott, looking distinctly un-Cannes. White tailored shorts and a T-shirt is fairly standard fare for this eternally aspirational town. However, a velour zip top and white trainers are about as far from textbook Riviera dressing as it's possible to get.

You'd have to have been living under a rock not to have noticed that formalwear has loosened up, and suits and sneakers is most definitely no longer a massive error of judgement but a whole - extremely comfortable - genre of dressing in its own right.

Now, it seems the rest of a man's gym wardrobe is getting in on the action. Those items that you're used to seeing in the changing room are no longer content being worn solely for the purpose of sweating and 'self-improvement'

Reiss Head of Menswear Design, Alex Field, says:  "Menswear has seen a shift towards a culture where relaxed dress codes and excellent craftsmanship are no longer mutually exclusive. Men who once aspired to a full suited look as a marker of good taste now have the option to buy into a luxury that’s stealthier, more effortless and ultimately more comfortable to live in. As a result, lines between formalwear and casualwear have become blurred, meaning that T-shirts and trainers are increasingly being worn with tailoring in place of shirts, ties and dress shoes."

So then, don't let sportswear just be your off-duty go-to, and instead incorporate key pieces into your formal wardrobe too. Below, we've listed the styles which you should work into your wardrobe.