Mary-Kate and Ashley Olsen
With their Full House and straight-to-home-video careers in the rearview mirror, Mary-Kate and Ashley Olsen set their sights on the sartorial world in 2004. The twins are unique among fellow celebrity designers for having created lines on both the high and low ends of the price spectrum. After conquering the mass market with a children's clothing line for Walmart in 2004, the twosome turned their focus on high fashion. They debuted the Row, which shows at New York Fashion Week, and the lower-priced Elizabeth and James in 2007 to capitalize on their fashionista reputation, and the joint ventures have proved well advised. Big-name fans include Heidi Klum, Jessica Simpson and Sarah Jessica Parker. In 2009, the Olsens added Olsenboye to their design repertoire, a diffusion line for teens sold at JCPenney, proving that it takes two to tango and design successful fashion lines.