Despite my hesitation, and subsequent humiliation, over wearing the OnePiece in public, it’s quite comfortable for lounging at home, and there is a growing market for such cross-over sleepwear, according to Wendy Liebmann, CEO of retail trend watchers WSL Strategic Retail.

“I remember that I had just broken up with my girlfriend and I thought ‘I’m just going to put on a purple OnePiece and see how people react.’ I got so much attention,’’ Adams recalls. “People said, ‘What the hell are you wearing?’ Everybody asked me, ‘Where did you buy it?’ And that’s when I realized that people would like to wear it everywhere.’’

They crafted this Frankensuit for a group of friends, and when others saw the newly christened OnePiece, demand began to snowball.

“Norway’s a cold country,’’ says Thomas Adams, one of the businessmen behind the OnePiece. “We were frustrated that the [hem of the] hoodie was always getting pulled up. We put some clamps on the sides to keep it in place. My business partner Hernia [Nostrud] said we should sew the hoodie to the sweat pants, and that became the prototype.’’

This unlikely fashion curiosity sprang from humble and somewhat nauseous origins: As the story goes, three hungover Norwegian 20-somethings were recovering from a night of carousing, and looking for something comfy and cozy to wear while they convalesced on the sofa the next morning.

While I feel ridiculous, my fashion choice has put me in good (celebrity) company. The OnePiece has been spotted on Lady Gaga, Jude Law, Katy Perry and husband Russell Brand, Justin Bieber , and fashionista/reality TV starlet Whitney Port. The OnePiece recently arrived in the United States with a splash, most notably showing up in a window display at trendy Los Angeles boutique Kitson. The OnePiece is currently not sold in Boston stores, but can be ordered online.

Despite feeling mortified that I would be the subject of a child’s nightmare that evening, I certainly couldn’t blame the poor girl for her outburst. I was strolling Copley Place wearing what I’m told is a fashion sensation in Europe and by all accounts will soon be spreading in the US faster than a potent strain of H1N1. It’s called a OnePiece, and it looks like toddler apparel for adults. Think of it as a Snuggie that has found a tailor. The giant, all-in-one sweat suit has a zipper that runs up the front, several pockets, and it leaves me resembling a Teletubby as I walk through the Back Bay. Reactions range from open mouths to outright chortling.

“It’s not polite to point,’’ said the mother, furrowing her brow and sweeping her daughter away with a swift and steady hand.

‘Mommy, what’s wrong with that man?’’ I heard a small child ask. I turned to see what the tot was looking at, and realized that she was staring directly at me.

“In nasty, horrible economic times, everybody just wants to stay in their pajamas and not emerge from their shell,’’ Liebmann says. “What we’ve seen is a modification of the sleepwear market. There have been more fashionable versions of the pajama pant, and there was the camisole trend. Suddenly, people are wearing pajamas all day. And then there was the Snuggie explosion. I think that it’s shown the fashion industry and retailers at large that you can have success in categories that — if you’ll excuse the expression — are a little sleepy.’’

From a fashion perspective, the OnePiece follows in the storied footsteps of trends such as the late 1980s bicycle short-as-every-day-fashion fad, and the 1990s bustier-as-blouse crossover, says professor Sondra Grace, head of the fashion department at Massachusetts College of Art and Design. While she was impressed that some OnePiece models feature on-trend details such as fair isle prints and color blocking, she was less impressed with the fit of the garment.

“I thought that there was a lot of attention paid to detailing,’’ Grace says. “Above the waist is good. But the crotch drop just didn’t win me over. The issue with a one-piece jump suit is that it might be comfortable, but at some point you have to go to the bathroom. If you’re out and about, that could be trouble.’’

Public restrooms and funny looks aside, there is enthusiasm surrounding the OnePiece from both the apparel business and trend followers. When the OnePiece arrived in the UK last year, bloggers and newspapers practically fell over themselves with sweeping proclamations that the funny-looking, pajama-like suit was “The winter trend of 2010’’ (this, from the London Evening Standard). Sally Lohan, of the fashion trend analysis and research service WGSN, says the timing of the OnePiece corresponds to the fact that more individuals are working at home and choosing comfort over style.

“There are definitely more of us tapping into the comfort-dressing trend,’’ Lohan says. “Jeggings, leggings, and other more casual looks have become acceptable attire in many workplaces.’’

While that may be true, I was generally mocked while wearing the OnePiece in the office. It takes a lot of self-confidence to pull off this look. Lacking this, I mostly hid at my desk. Explaining to co-workers that Lady Gaga and Perez Hilton have worn the OnePiece simply made their laughter louder. But Lohan explained that the OnePiece’s celebrity following could help bolster its popular, despite its unusual appearance.

“Celebrities can definitely influence purchasing decisions,’’ says Lohan. “After Jessica Simpson appeared in a photo wearing a Rebel Yell T-shirt at an event for the brand, Kitson sold $300,000 worth of the tees in one month.’’

But like many trends — think Ugg boots — the OnePiece has been the subject of heated conversations and nasty comments around the blogosphere. Adams, one of the creators of the sweat suit, sounds almost proud of this fact.

“What we love about the product is that it generates so much debate,’’ he says. “Either people love it, or just totally hate it. It’s amazing how people can have so many feelings about a piece of clothing.’’

Christopher Muther can be reached at muther@globe.com.

© Copyright 2011 Globe Newspaper Company.