once upon a time, celebrities were happy to slap their names on merchandise and take the money.

Now some are emerging as full-fledged designers. Katie Holmes, celebrity stylist Rachel Zoe, Victoria Beckham, and Mary-Kate and Ashley Olsen all are showing off their looks for spring and summer 2013 at New York fashion week, the semi-annual stylefest that continues this week. Beckham’s line debuted Sunday, while Holmes’ and Zoe’s shows will be Wednesday.

The emergence of celebrity fashion designers is helping some retailers boost women’s apparel sales, which struggled in the wake of the downturn. Zoe’s collection has sold well at Neiman Marcus Group, according to Ken Downing, the department store chain’s fashion director.