Nicole Richie, John Varvatos, Elle Macpherson, Jessica Simpson

At first glance, NBC's upcoming Fashion Star may sound like a knockoff of Lifetime's Project Runway and Bravo's The Fashion Show. But executive producers, including original Runway co-creator Jane Lipsitz, insist Fashion Star goes one step further.

As host and executive producer Elle Macpherson told reporters at NBC's winter TV preview Friday, it was important to "create a show that was just as much about shopping as it was about fashion."

Premiering Tuesday, March 13 at 9:30/8:30c, Fashion Star's aspiring designers are judged not by fashion magazine editors or designers, but by buyers for Saks Fifth Avenue, Macy's and H&M. The buyers place competing bids on fashions they like and, also unlike Runway and Fashion Show, viewers will then be able to buy the clothes online immediately after the episode airs and the next day in stores. "You're voting with your pocketbook and you can wear the winner," executive producer (and former NBC Entertainment Chairman) Ben Silverman said. "This show lives and breathes because H&M, Macy's and Saks are in it. They make it that much better."

Check out photos from Fashion Star

The series was filmed in July and August to ensure the finished clothes would be ready to wear in time for the show's launch. Designers are mentored by celebrity designers including Jessica Simpson, Nicole Richie and John Varvatos and then present their clothes in runway shows that Silverman compared to Victoria's Secret annual televised fashion show.

In any given episode, the buyers will have to compete against each other to carry particular designs exclusively in their stores. But in the end, the winner will be featured in all three stores in a prize Silverman values at more than $6 million. "The competition in the show is really fierce and fun," Silverman said. "They are investing their own money in the prize. They are creating the prize, which is valued over $6 million for the winning designer."

Adds Macpherson: "It's for every women and every pocketbook. It really allows people from every economic situation to tap into what retailer works best for them."