Although these ones don't come with any mop fibres dangling from the front, many fashion experts are at a loss to explain why adult onesies have become something of a trend this fall.
And we're not talking about cute rompers either. The Daily Mail has photos of adults wandering around in public in what looks like a pair of giant pajamas.
"Last year the onesie made up just one per cent of total sleepwear sales and it has now jumped to 15 per cent," a spokesman for Marks and Spencer tells Express.co.uk.
"If you are yet to encounter one of these ludicrous garments, then think of a Babygro, add a hood, supersize it and you get the idea," writes the Mail's lifestyle columnist Charlotte Kemp.
"Ridiculous though they sound, they're on sale across the High Street, from John Lewis to New Look, and the recent cold snap has resulted in a surge in sales."
Higher-end shops around the U.K. have even started moving their models in bulk as the onesie transitions from bedtime garb to daywear.
The Telegraph also sent out a roving reporter to brave the new onesie trend amidst high pedestrian traffic on a London street. This was his reaction:
"This is the fashion world's two‑fingered salute to square bears such as me who choose to wear a jacket and tie to work," he writes.
While the trend seems to be exploding most rapidly across the pond, with Kate Moss and designer Stella McCartney serving as its high priestesses, American style celebrities, like Sarah Jessica Parker and Brad Pitt have also been spotted sporting the look.
In Canada, where winter is perched around the corner with its icy fingers, the idea of snuggling into a soft, cotton one-piece before braving the elements can seem like a welcome idea.
We've even got our own version — somewhat of a portable Snuggie with legs — from online retailer Forever Lazy.
But as a fashion piece you try to pull of at the office? Depends on your workplace dress code. They might just be too crazy even for casual Fridays.
What do you think? Completely cute or heinous abuse of fabric?
Watch the video below taking a close look at Khloe Kardashian's style.