The cropped top and matching pencil skirt are staging a comeback so sleek that it's surely on the way to silhouette-of-the-year status.

Nearly every runway designer or private label took a stab this spring at this version of matchy-matchy:

Alexander Wang created a trés sexy version for Balenciaga that featured a ribcage-grazing midriff in black leather and a matching sheer skirt.

Humberto Leon and Carol Lim dropped their cropped tops to the waist for Kenzo. Fashioned from white eyelet fabric that's patterned to look like smiling emojis, these skirt-and-top ensembles are perfect for happy, summer days.

Zippers dictate the depth of slits on neoprene skirts by emerging label Kiind Of. And Nicole Miller splashed florals on curve-skimming, yet work-appropriate, complementary separates for her eponymous runway label.

"What I love about this look is that it's sexy, proportioned, and fresh," said Mary K. Dougherty, owner of the two Philadelphia-area Nicole Miller boutiques. "It's a very fresh approach to two-pieces."

It looks as if designers have finally hit on a replacement for the one-piece dress, the go-to through the early 2000s that took women seamlessly from day to night. (It's not bad for retailers, either, because they can sell you two items with a price tag that likely would rival one dress.)

Part of the beauty of this season's sophisticated high-waisted skirt-and-cropped-top combo is that, like the fit-and-flare frock from two fall seasons ago, the matching separates accentuate the slimmest part of a woman's body - her natural waistline.

But, so as not to make her feel pigeonholed into one look, there are a variety of cropped-top lengths trending. Some reveal abs: Think Kim Kardashian in a clingy slate-gray midriff and pencil skirt now the subject of a January bathroom selfie.

While others are more demure: Margot Robbie in the cornflower print, tummy-hiding (yet, still cropped) blouson with an A-line skirt in June at a charity event.

This spring, Maureen Doron, owner of Bryn Mawr boutique Skirt, is carrying looks from brands such as Theory and A.L.C. that reveal lots of skin, a sliver of skin, or, thanks to really high-waisted skirts, no skin. But when she first saw all the midriff/skirt sets in September while shopping the New York showrooms, she was "terrified."

"I didn't know how they would retail. I mean, they look great on models, but are real women going to buy them? So far, the answer is yes, they are buying them because designers are playing with illusion."

Even though blazers aren't an official part of the look, the matching separates have a modern-day suit quality to them. And for young women who were barely tweens when Ally McBeal first wore matching minis and jackets back in the late '90s Fox series, this updated look can make them feel put together in the same kind of dressy, professional way.

 The rest of us, exhausted by the busy business of correctly mixing nautical stripes with tiny florals or oversize polka dots, are happy that dressing up can now be easy, clean, simple, and feminine.

"Confidence is coming back on two levels," Dougherty said. "Consumer confidence is back where people are willing to try new pieces that move them. As women continue to evolve, we don't minimize who we are professionally just by being fashionable."

Matching separates have their roots in the Renaissance era, when dressmakers started to create two-piece constructions, after centuries of the one-piece robe, said Marcella Milio Martin, an adjunct professor of the history of costume and textiles at Philadelphia University.

"It was a unified look," Martin said of those first matching outfits. "It wasn't until the 1700s when women began wearing two pieces with something that looked like a blouse on the top and a skirt on the bottom."

The first time coordinating suits became trendy was in the 1940s, when teenagers wore midriffs and matching A-line skirts or shorts to beaches and picnics. In the 1950s, separates were more grown-up, but the skirts were fuller.

During the next decade, such designers as Mary Quant, Pierre Cardin, and Andre Courreges, inspired by the youth revolution, turned the two-piece set into high fashion, Martin said.

The 1980s brought with it rayon separates with button-down blouses - some with shoulder pads - and full, long skirts. And by 1998, when Carrie Bradshaw and crew unabashedly mixed tutus with plaids in HBO's Sex and the City, matchy-matchy was declared so over.

Fast forward to 2012, and model Dree Hemingway wears a chili-pepper-print midriff top and matching A-line skirt, courtesy of Dolce & Gabbana, to Coachella.

"From that point on, it gained traction," Martin said. "In the beginning of 2013, it was very 'street-chic' style. By the end of 2013, it was part of the core wardrobe."

Taylor Swift - spotted in separates from H&M to Alice + Olivia - has turned the art of matching separates into her signature style. Beyoncé has been photographed in a graphic black-and-white matching suit from Top Shop. And Ariana Grande likes the skirts in her very belly-baring skirt-and-top outfits to be A-line.

"There is something very familiar with this look, and people take solace in that," Martin said. "Fashion is supposed to make us feel good. And this look is feminine and fun. It feels good. Women are seeking it out."

SPECIAL THANKS TO:

Hair: Ashley Brown, Moko Organic Beauty Studio, 55 N. Third St., 215-922-6656.

Makeup: Vanessa Rivera, Salon Rosa M, 948 Montgomery Ave., Narberth, 610-771-9900.

Model: Claire Mahoney, Wilhelmina Philadelphia.

Assistant stylist: Mark Anthony Barksdale.

Clothes and Accessories: Ellelauri, 114 S. 19th St., 267-457-5939, www.ellelauri.com; Macy's Center City, 1300 Market St., 215-241-9000; Nicole Miller at the Hyatt at the Bellevue, 200 S. Broad St., Philadelphia, 215-546-5007; Peter Kate, 3830 Kennett Pike, Greenville, Del., 302-656-7463; Safian & Rudolph, 701 Sansom St., 215-627-1834; Theory, 1616 Walnut St., Philadelphia, 215-735-1034.

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