Gap Inc.'s fitness apparel brand Athleta is planning its first-ever designer collaboration with the Derek Lam 10 Crosby brand.

The athleisure collection will incorporate Lam’s minimalistic aesthetic and feminine sensibility with Athleta’s performance fabrics and fitness expertise.

Launching in stores in September, the collaboration will span three seasons, encompassing fall 2015, winter 2015 and spring 2016.

The first collection will include leggings, shorts, dresses, jackets, sweatshirts and sneakers.

“We’re excited to collaborate with partners who share Athleta’s passion for fitness and style and understand that the modern woman lives her life on-the-go,” says Nancy Green, president, Athleta. “Versatile clothing with elevated style that takes her throughout the day is incredibly important to our customer. Derek Lam 10 Crosby is the right brand to expand Athleta’s offerings.”

The collection will be sold online at select Athleta stores, at the Derek Lam 10 Crosby boutique in New York City’s Soho district and on the Athleta website.

“Our customer leads a very active lifestyle,” says Lam. “Fitness is very much a part of it, and we always strive to create clothing that works in her life. Athleta’s expertise in performance fabrics and fibers has offered us a really exciting opportunity to create a collection that complements perfectly what we do for Derek Lam 10 Crosby.”