JCPenney is tapping into a $17.5 billion market with a new plus-size clothing line

JCPenney is trying to grow its share of the $17.5 billion plus-size apparel market with a new clothing line targeting curvy millennials.

The new line, called Boutique+, will be JCPenney's first line designed exclusively for plus-size women.

The retailer has hired reality TV star Ashley Nell Tipton, who famously was Project Runway's first-ever plus-size winner, to help promote the new brand.

Tipton will be designing two capsule collections for Boutique+.

The line will launch in May, according to an Instagram post.

"There are millions of incredibly stylish full-figured women who are seeking comfortable, well-fit clothes that offer style and versatility," Siiri Dougherty, JCPenney's senior vice president of women's apparel, said in a release. "JCPenney is committed to winning her loyalty by designing an entirely new modern brand made just for her and creating a dedicated shopping environment that respects her time and budget with a greater selection of affordable plus-size fashion that takes into account diverse body types."

The plus-size market in the US is huge. The average American woman is a size 14 and 65% of US women are considered plus size.

JCPenney is trying to tap into that market with the new line. The retailer has also said it's working harder to promote in-house brands as part of its turnaround efforts. CEO Marvin Ellison told Fortune in February that zeroing in on the company's in-house brands was a key part of his business strategy.