Gap isn't all about jeans anymore.

The company is investing heavily in its Athleta activewear business, reports Sapna Maheshwari at Buzzfeed.

"My generation grew up wearing jeans — jeans are just a part of our life, and it still is, Athleta executive Nancy Green told Buzzfeed. "But this generation is growing up in yoga pants and activewear. So I think it’s just going to be bigger and bigger and bigger for the future."

Athleta has more than 100 stores and is expanding fast. The brand is seen as Lululemon's biggest competitor.

Gap's namesake and Old Navy brands are also including more leggings and jogger pants.

Denim sales have been declining in recent years, while stretchy athletic pants are exploding in popularity.

Teens are increasingly buying gear from Nike and Lululemon over denim classics from brands like Abercrombie, according to a recent Piper Jaffray survey on teen spending.

Gap recently posted this photo of a model wearing leggings to its Facebook page. Gap on Facebook.

Nike, Lululemon, Under Armour, and Adidas are the most popular brands for athletic apparel.

Leggings, especially yoga pants for Lululemon, were ranked as the most popular trend among female teens, according to the report. Jeans were not named in the top 10 trends.

Here's a chart showing the decline of denim and rise of activewear with upper-income females.

Men are becoming more comfortable with the idea of activewear too.

Lululemon's men's line is growing faster than its women's business.

Executives say that men especially love its anti-ball crushing pants, which combine the feel of athletic pants with the look of trousers.