In Her Fashion: Jerry Who?

At a recent fashion trade bazaar in Manhattan, designer Shoshanna Lonstein was giving the hard sell to a group of potential clients. Sporting one of her new fall designs--a strapless wool tube dress--she looked herself up and down, fidgeted with the top of her dress and began, "I've made my clothes to allow for a woman's body, if you have one." Said a buyer from Miami, giggling: "Like you certainly do!" While the crowd burst out laughing, someone in the back whispered, "Hey, isn't she the one that used to go with Jerry Seinfeld?" The answer, of course, is yes, but everyone was too busy filling out order forms to respond.

Seinfeld is making the gossip columns with another girlfriend these days, but Lonstein has not relinquished her 15 minutes of fame. Though it debuted only last fall, her collection of lingerie-inspired dresses, with matching handbags and thongs, nearly sold out at Bloomingdale's in three days--"even though they were cotton clothes in November," notes the store's fashion director, Kal Ruttenstein. There are waiting lists in some boutiques for her outfits, priced at an affordable $130 to $160, and her 50-piece sportswear collection will be in 200 stores by June. Sales are expected to top $1 million in 1999. Not bad for a girl who's only 23 and still lives in her parents' apartment on Fifth Avenue.

At last month's runway shows, Lonstein grabbed as many flashbulbs as visiting celebs like Julia Roberts. More surprising, the fashion world is taking her seriously. She's had doting spreads in the major women's magazines; last month Cosmopolitan even named her a contributing editor (job description: "providing trend updates, supplying party reports"). "Her designs are like Barbie-slash-Hello Kitty with Liberty of London mixed in," gushes designer Betsey Johnson. "Kind of Brigitte Bardot and beyond." Translation: low-cut frocks made of girlish fabrics such as dotted swiss and gingham, in pale pinks and blues that run completely counter to minimalist chic. Even her ex is applauding her new venture. "I'm a big fan," Seinfeld told TIME.

Raised on Manhattan's Upper East Side, Lonstein began designing clothes out of necessity: she made her own bras and bathing suits when she had trouble finding any to fit her ample breasts and pencil-thin lower body. "I love clothing more than anything else," she confided over hot cider at a neighborhood lounge. "I almost walk through stores like one would walk through museums." After graduating from U.C.L.A. in 1997 with a dual degree in history and art history, she apprenticed at a lingerie company, where she learned that "it takes 38 pieces to construct a bra." Then her father Zach, who has a computer business, lent her money to help form a company. "We never thought she'd work so hard. She even stayed home last Saturday night, which she didn't used to do during school exams," says Zach, who often talks shop with his daughter at 5:30 a.m. while he's on his treadmill.

Shoshanna insists that her Seinfeld connection is not the reason for her success. "I don't link it with my past at all," she says. "Maybe you think that's naive." Her breezy manner turns prickly whenever Seinfeld enters the conversation. When a correspondent for CBS' 48 Hours, interviewing her for an upcoming show, popped a question about him, she stormed off with the camera still rolling.

The fashion world, at least, seems to be taking her on her own terms. Buyers at the trade show were snapping up her fall line--though a few were disappointed there were no matching winter-weather thongs. "The very thing that captivated Seinfeld is captivating everyone else," says Kate White, Cosmo's editor in chief. "He fell for her because of her beauty and charisma, and so have we." Now the question is whether it's a spring fling--or a love built to last.