From posh Saks Fifth Avenue to budget-conscious Steve & Barry's, shoppers can now find everything from yoga wear to lingerie designed by celebrities. And there's more to come.
This month, Spice Girl Melanie Brown unveiled a clothing line inspired by leopard prints, while Heidi Montag of MTV's "The Hills" launched a collection of junior apparel called Heidiwood.
In the summer, teens can expect to see singer Avril Lavigne's "rock glam" style at the local mall in time for back-to-school shopping and a beachwear line from actor Matthew McConaughey.
Celebrities and the fashion industry have long shared a symbiotic relationship. After Grace Kelly was photographed trying to hide her pregnancy with a Hermés bag in 1956, demand for the crocodile handbag soared. Today, lesser-known designers have seen their sales spike when stars have been snapped in their designs, everywhere from the Oscar red carpet to casual Starbucks runs.
Buoyed by their influence and the success of brands headlined by famous names like Gwen Stefani and Sean "Diddy" Combs, a growing number of celebrities have been crossing over to claim the "fashion designer" title in recent years.
Retailer Macy's, which carries merchandise from the likes of Jennifer Lopez and Donald Trump, has centered its current advertising campaign on these Hollywood designers by featuring Jessica Simpson and Combs in its television ads alongside established names like Tommy Hilfiger and Kenneth Cole.
Designer Yeohlee Teng, who studied at Parsons before establishing her own successful design house in 1981, welcomes the trend if it heightens the awareness of fashion and "makes available a lot of different ideas at many different price points" for consumers.
But the expanding list of celebrity designers has some thinking that when it comes to landing a label deal, a star pedigree may be more valuable than a degree from Parsons.
Joanna Mastroianni, a New York-based designer who has dressed stars like Eva Longoria and Beyoncé, is concerned about the increased attention and resources going to famous faces.
"There are a lot of hardworking people in our industry, but dollars from the stores, store space, press and everything else does not necessarily go in that direction," said Mastroianni. "And there's something a little disappointing about that."
Both Mastroianni and June Weir-Baron, a former editor at Vogue and Women's Wear Daily, agree that in this celebrity-obsessed culture, it is easier for retailers to sell a brand with built-in name recognition and publicity than to gamble on a talented unknown.
Some of the distinguished brands are also not immune to the shift.
"It doesn't make it any easier when you see good houses like Dana Buchman and Ellen Tracy having a really hard time getting space in stores. And on the other hand, you have people who have never even been in a studio or workroom doing just fine," said Weir-Baron, who now teaches at Parsons and New York University.
Mastroianni, who presented her collection at the 2008 Fall New York Fashion Week, likened the trend to a designer deciding to record an album by hiring the best resources available and labeling herself a singer.
"There is something very misleading about it when we start to believe that these [celebrity] brands are designers. They're not designers, they're brands that are being created. There is a difference."
Some stars concede that they are collaborating and not necessarily designing the merchandise that bears their name.
When Natalie Portman spoke to ABC's Diane Sawyer about her new line of animal-friendly shoes, the actress stated, "I don't really know how to design a shoe but I bring what I like. I'll bring pictures or old shoes that I have and show them, and they draw something and I say, 'Maybe the heel could be different.' … That kind of a process."
While most celebrity designers do not have formal education or industry experience, there are exceptions.
Adrienne Jones, a professor of fashion design at the Pratt Institute, points out that Tina Knowles had a background in design as a stylist for Destiny's Child before launching her House of Deréon line with daughter Beyoncé.
Kimora Lee Simmons, the creative director of Phat Fashions, got her start in the industry at a young age modeling for Chanel designer Karl Lagerfeld.
Still, Jones questions how much celebrity fingerprint the designs carry.
"The bottom line is there is a real designer behind the line," said Jones. "Most of these people might come over and look over some sketches but it's the fashion industry that's supporting them and holding them up."
Which is why some design students looking for employment after graduation don't mind seeing "Stuff by Hilary Duff," "William Rast by Justin Timberlake" or "Bitten by Sarah Jessica Parker" on the racks.
"It gives a lot of opportunities for designers because the celebrities don't design. They have to hire new designers and I don't think it's a bad thing," said Genevieve Fernety, a student at the Fashion Institute of Technology in New York.
Jennifer Yoo, a Parsons grad, agrees.
"As much as there's a negative aspect to it, we know that it's people like us who work there."
Fashion designer Francesca Sammaritano who is now a professor at Parsons says these labels can serve as a springboard for her students who are just starting out.
"When they graduate, some of them need the exposure and the experience of working for a company to acquire hands-on knowledge and get all their networking contacts before they go on and begin their own company," said Sammaritano.
Then there are those who don't see it that way. Juan Herrera, a fashion design student, thinks the celeb designers "don't see fashion as an art form," but rather as an "economic sustainability for their business."
And although FIT student Kimberly Stack understands that fashion and Hollywood go hand in hand, she doesn't welcome the stars' forays into her world.
"It's disheartening because we're putting in the work to study it and learn the business and the science of it," said Stack.
The recent popularity of fashion-based reality shows like Bravo's "Project Runway" has shed light on the science of designing to industry outsiders, but the growth in clothing lines from stars who don't have obvious ties to fashion design worries some insiders who feel the trend may undermine their art in the public's eye.
"Many people think designing is drawing little pictures and not making decisions. People don't really understand the process of creating a concept, how everything is combined," Herrera said.
"Anyone could be a designer, but not everyone can be a great designer," said Mizy Kim, a designer at American Rag. "Being a great designer is not just about sketching and having great ideas or being a good shopper. It's more than that. There's so much to learn."
Despite any objections, Kim doubts most working designers would forgo the option of taking the celebrity route if given the chance, a sentiment echoed by Molly Lunn, an accessories design student at FIT.
"They have the power, might as well take advantage of it. I would."
So what would it take for a talented designer without the name recognition to achieve the same level of individual success as say, Jennifer Lopez? Lots of money, not to mention hard work. But mostly money.
Jones says launching a label is an expensive gamble for even the most gifted designers and the struggling economy doesn't help.
"Until the nation is out of this financial mess, I don't really see a lot of people being able to take that financial risk," said Jones. "And finding backers at this point is slim to none."
The struggling economy will also be a test to the staying power of the celebrity designer brands.
Weir-Baron wonders how consumers with less disposable income will react, asking, "Are they going to be spending as much money on frivolous clothes?"
Ultimately, retailers will follow customer demand, as Macy's did when it stopped carrying Nicky Hilton's line of casual wear because of poor sales.
Even fashion maven Victoria Beckham was recently plagued by rumors that her dVb denim line was on the verge of being dropped by prominent Los Angeles boutiques Fred Segal and Kitson, while rapper 50 Cent's G-Unit line severed ties with its parent company and shut down its offices earlier this year.
While no one is sure how long the trend will last, everyone agrees that the one thing Calvin Klein and Lopez have in common is their right to pursue their interests.
Malaysian-born Teng concluded, "Being an American, I like the spirit of enterprise."