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."