Jessica Simpson is no stranger to designing fabulous clothing styles for adults of all shapes and sizes. Now, with the help of her little sis Ashlee Simpson, she is gearing up to launch a line of tween apparel as part of the Jessica Simpson Collection hitting stores this fall.

The new products will be geared toward the fashion-forward tween, featuring various styles that will include sportswear, activewear and denim, all styled with Simpson’s "girly, playful attitude."

The collection will also feature knit tops, hoodies, pullovers, striped shrunken knits, graphic T-shirts, drawstring pants, footwear and outerwear -- all designed by the superstar sisters who both serve as co-creative directors for the clothing line.

"Creating a tween apparel collection was a natural extension for the brand," Jessica tells WWD (quote via PEOPLE). "I’m excited to bring my sister along as co-creative director of this division, because she brings a savvy rocker edge that defines today’s tweens."

"My goal as co-creative director will be to design clothes that will help inspire young girls to express their personalities and creativity through fashion," adds Ashlee.

The new collection of clothing for the Simpson sisters marks the first time they have collaborated on a fashion venture together. Look for the Simpsons' new clothing line to hit stores this fall.

Watch a Recent Interview With Ashlee and Jessica Simpson