Michael Glasser, who created premium denim brands 7 for all Mankind and Citizens of Humanity, has partnered with Gwen Stefani on a new line.

The 18-piece collection is known as DWP (for Design With Purpose), and is set to hit stores in Spring 2014. The cornerstone of the line is the pant - a slouchy, cropped and tapered trouser in Tencel, treated and coated like luxury denim. In fact, the pair initially wanted to found an eco-conscious denim line together, but decided the market was already saturated.

"A buyer from Neiman Marcus came up to me and said, ‘If you show me another five-pocket jean, I'm going to punch you.' So I thought, ‘Do I really want to show a new jeans line? I don't think so,'" explained Glasser to WWD. The No Doubt singer, well known for her own distinctive style, was on board with the idea.

"I was trying to get all the basics. Michael nailed the bottoms," added Stefani. "For tops, I was trying to think about what I wear besides a tank top. I love cuffed-up sleeves, tops that are long in front and short in back. And we did a jumpsuit and a dress to fill in the gaps."

Ten years ago, Stefani founded her first fashion and accessories label L.A.M.B. following it up with clothing and lifestyle brand Harajuku Lovers, which will get its own 52-episode girls cartoon, as well as a second fragrance, in 2014. Gwen's nail color collaboration with OPI has also just hit stores.