It's the skin-tight fashion trend that has taken gyms by storm.
But now there's a new twist on the figure-hugging shorts women are sporting to complete their workouts – and it's definitely not for the faint-hearted.
A nude version of the Lycra bike shorts that have been cropping up all over Instagram has recently been released and at first glance it looks as if the wearer isn't wearing anything at all.
The risque design from Australian activewear brand Echt costs A$52 ($57) and comes in a range of shades including some nude tones.
But when worn by individuals with a similar skin colour, it looks like they're wearing nothing at all.
A Brisbane model recently posed in flesh-coloured shorts and a matching bra, prompting several people to point out it looked suspiciously like she was in the buff.
"I had to take a second glance," one wrote.
"Honestly thought you were naked for a second," another added.
The daring outfit choice – which is designed to give the wearer a "stylish silhouette" according to the brand's website – hasn't just been spotted on models, with everyday women wearing them to the gym.
One woman from the United States turned heads after taking a mirror selfie at the gym in a "Cedar" pair of the "Scrunch Shorts" while another had a similar effect in the "Taupe" pair.
There are also full length leggings available in the "naked" colours, also causing double takes.
The shorts, which also feature a ruching detail on the bottom to enhance the body's natural shape, have soared in popularity and caused a stir at some gyms.
Sydney woman Gabi Goddard recently hit the headlines after revealing she was "asked to leave" her Hornsby gym when wearing a pair of the grey Echt shorts for her workout.
She later realised she had the shorts on inside-out - meaning people had mistakingly believed she was wearing a G-string on top of her pants – but remained firm the gym was in the wrong for telling her to go home and change.
A Sydney couple however have benefited from the surge in popularity in the bike shorts, earning A$250,000 in 30 minutes with a collection of the Lycra pants.
STAX creator Don Robertson and partner Matilda Murray said the risque trend – which has been popularised by Hollywood's elite and festivalgoers – is here to stay.
"It's officially (almost) bike short season, which go perfectly with an over-size tee or crop top," Murray told news.com.au, adding they chose to focus on making a range of celebrity-style shorts as they were "proving to be extremely popular, both inside and outside the gym".
"We've even seen a few boys rocking them so we're working on making them a men's item too."