Jessica Simpson and Ashlee Simpson are tapping into the tween market! The sisters will serve as co-creative directors on The Jessica Simpson Collection's new line of sportswear and jeans for girls sizes 7 through 16. “She brings a savvy rocker edge that defines today’s tweens,” said Jessica Simpson of her little sister and new collaborator to WWD. Shoppers can expect to see fun items like faux fur vests, colored jeans and graphic T-shirts. The line will be available at 400 retailers by the end of the year, including Macy's, Dillard's and Lord & Taylor.