Currently in store at the Gap are the limited edition white shirt designs of the Vogue/CFDA fashion finalists Thakoon, Rodarte and Doo.Ri -- all emerging American designers. Priced between $68 and $88, they're available in the United States, Canada, United Kingdom and Japan.
Uniqlo, which will collaborate with eight designers, began with New York-based Alice Roi on May 3 at their flagship store in Soho. Roi's range, priced between $49.50 and $69.50, sold out of four styles almost immediately. Roi's range is also available at 900 doors in Asia.
"We can't disclose figures, but these collaborations are very lucrative for the designers," Marc Beckman, CEO of Designers Management Agency (DMA), who represents his wife Roi, told ABC News. "Designers get a creative fee, they make royalties from sales, a personal appearance fee and they get usage rights."
Silverstein estimates that "the royalty payment is usually between 2-6 percent, the gross profitability 65-75 percent, and the operating profit is in the high teens."
Moss has been paid an estimated $6 million up front for her first collection, an amount that Green told the U.K. Daily Mail newspaper is "merely the tip of the iceberg." It is rumored that, after royalties, she could take home well over $20 million.
In the United States, the success of celebrity-led fashion brands like Jennifer Lopez's J.Lo brand and P.Diddy's Sean John range is not news.
At H&M, the retailer raised the bar with a collection designed by Madonna and reportedly saw its March sales climb 17 percent. H&M will follow the success of that collection with one by Kylie Minogue.
"With Madonna, H&M has been able to raise its game in the United States as a much hotter brand. Kate Moss could do the same thing for Top Shop," Bernstein Research's Luca Solca told Reuters.
Green has told the U.K. press that his partnership with Moss is about a building a multimillion dollar brand with longevity and not just a one-off collection.
Of course, Madonna, Minogue and Moss are not trained fashion designers. But do consumers really care?
Beckman said, "If it's designed well and it's doing more than just making some noise then it's wonderful."
However, in the United States, the press remained unconvinced. New York magazine wrote that the clothes look like they've been designed for "the hungry and the sullen." Portfolio.com blogger Lauren Goldstein Crowe described them as "pretty average, verging on ugly at times." The supermodel has also been criticized for only catering to sizes 0-6.
"We have a rule of thumb at BCG which we call the 10:300 rule," said Silverstein. "If you satisfy a consumer, she'll tell 10 of her friends. If you disappoint her, she'll tell 300. She's retaliative in some ways. If the item is below quality, the consumer will take it out on you."
Is this a passing trend?
"Masstige is a 10-year movement that still has wind behind its back," Silverstein said. "There's been a huge sociological change in the U.S. over the past decade. Women are doing 85 percent of the spending."
Target's Walter said it is difficult to predict industry trends. GO will be evaluated based on how well it continues to resonate.
DMA's Beckman, however, said that this is no passing trend. "It's the human condition. We want what's best. And now that consumers have been given a taste of luxury, of great design at the mass level, why would they allow for anything but that?"
One thing's for sure, there's no end to the trend at Top Shop.
According to the London Paper, Top Shop is already talking of diversifying Kate Moss Top Shop.
"We're looking at luggage and other products such as vanity cases and a special edition for Christmas," said a spokesperson.