Celebrities and style icons have long been wearing slips, corsets and bustiers outside the bedroom, from Elizabeth Taylor and Madonna to Gwen Stefani, Rihanna and Lady Gaga.
But if you're wondering whether that lace-trimmed camisole under your co-worker's blazer is from the lingerie or outerwear section, you're not alone.
Lingerie-inspired looks that are made to be seen are emerging from the boudoir and onto runways, the red carpet and all the way into street style blogs and even the office.
At Lingerie Fashion Week in August, the prominence of loungewear -- pajama tops and bottoms, tap pants -- and chemises in bright colors and bold patterns underscored designers' efforts to create pieces that can be worn for any occasion. Lingerie-inspired looks are also popping on the runways this week at New York Fashion Week, most notably from Jason Wu, whose line included corsets and jackets with sexy details and shimmery gowns in soft palettes, marking a departure from his previous formal fare.
Thanks to several innovative brands and designers, "lingerie as outerwear doesn't just mean letting a camisole peek through your blazer anymore," said Cora Harrington, founder and editor of The Lingerie Addict.
It could mean pairing a lacy bodysuit with jeans and blazer; bandeaus, bralettes and longlines under tank tops; sheer slips and petticoats over leggings or under skirts.
And, yes, it can be classy if done the right way, experts agree.
"Part of it is the consumer's desire to create a unique look. A flash of lace or a luxury bra under a sheer top tends to draw more attention than the sparkle of jewelry," said Luis Paredes, publisher of online trade magazine the Lingerie Journal. "Brands and retailers have also become very savvy in fueling this trend by helping their consumers pair ready-to-wear with intimates."
With celebrities sporting bustiers, corsets and high-waisted knickers as part of their looks onstage and off, it was only a matter of time before it caught on in mainstream fashion, said Aline Machado of Bella Bella Boutique, an online lingerie store that demonstrates how to translate lingerie into ready-to-wear looks (and vice-versa) on its blog and Pinterest page.
"The trend is widely being shared among fashion bloggers around the world," Machado said. "Fashion magazines have been showcasing editorials with lingerie as outerwear and lingerie inspired-looks. Lingerie designers are creating key pieces in their collections that are easy to incorporate with outerwear looks and are meant to be seen."
High-end fashion brands have been known to incorporate lingerie-like items and details into their collections, from Dolce & Gabbana's bodysuits and bustiers to A/W 2013 Louis Vuitton's slips, tap pants and dressing gowns, said Harrington, who also credits the popularity of burlesque and style icons like Dita von Teese with propelling the trend.
Some dedicated undergarment brands began flirting with outerwear out of necessity. When consumers started scaling back during the recession on luxury purchases like high-end lingerie, some designers began marketing intimates as crossover pieces.
Other brands saw it as an opportunity to diversify as savvy shoppers began taking chances with mixed prints and styles.
"Today, the concept of mixing seems to be bolder and bigger than ever and it's validating the trend of lingerie as outerwear," said Shelah Jean, co-founder of NOE Undergarments, whose lambskin corsets and sheer jumpers make a statement wherever they're worn.
"People are mixing designers, high-end and fast-fashion, styles of all sorts. They're taking chances, which is great for us."
Compared with the days when Madonna was voguing in leather corsets and cone-shaped bustiers, the look is also becoming more relaxed and casual. That's good news for emerging designers like Kriss Soonik, who uses the term "loungerie" to embody her twist on underwear as outerwear.
In addition to traditional bras and panties, her collection also features lace bodysuits and mesh dresses ideal for layering; polo shirts with suspenders that can be attached to thigh-highs and kimono-style gowns that can be worn as blazers or jackets.
"For me, I always wanted to create something that had a multipurpose tag to it," the Estonian designer said in a phone interview from her base of operations in London.
"When you buy something quite expensive and can only wear it to seduce someone and tuck away in your drawer, that's quite a sad thing."
Thanks to the Internet and personal style blogs, the line is blurring as customers become bolder and more daring.
"They're looking for things they like. And they don't care if it's in the lingerie section or outerwear section," she said.
Intrigued? While there are varying lengths to which one could take the trend, our experts recommend sticking to the "chic and elegant" side of things, unless you're getting ready to hit the stage with Robin Thicke.
I think of lingerie as outerwear as occupying four main categories, at least from what I see (and what's accessible to most women).
You have what I call the basics of lingerie as outerwear, which are items like lace trimmed camisoles. They're versatile and functional and they look great on a variety of body types under a cardigan or blazer. Gold Hawk, Farr West, HoneyCooler Handmade and Natori all make beautiful, lacy camisoles.