People shop in a COS (Collection of Style) store in Berlin. A brainchild of Swedish giant H&M, COS is expected to fill the gap between pricey high fashion and cheap wholesalers. - 

The fast-fashion retailer H&M is debuting its high-end spin-off brand, "Collection of Style," in pop-up stores in the U.S. next week. The brand, COS for short, is an upscale line that aims to mimic the look of popular fashion brands, such as Prada or Jil Sander, while keeping costs down. The company is scheduled to open full stores in the U.S. later this year.

"It's much less expensive, and it's hip in a way that I don't think fast fashion has had this hip kind of attitude before," says fashion journalist Kate Betts, author of the book, "Everyday Icon: Michelle Obama and the power of style."

COS has stores in Europe, Asia and the Middle East. It's only now starting to venture into the American market, with plans to open stores in New York and Los Angeles.

Betts points out that COS has a viable market in the U.S.: "The retailers, the department stores have given women the habit of buying everything on sale, so they're not going to pay full-price for anything anymore."

Follow Kai Ryssdal at @kairyssdal