Costello Tagliapietra's draped T-shirt dresses for Uniqlo hits stores April 21. Courtesy photos.

It's their turn.

American design houses Charlotte Ronson, Costello Tagliapietra and Vena Cava made the Spring-Summer roster of collaborators for Uniqlo's Designer Invitation Project.

They join six other brands -- Zechia, Tiny Dinosaur, Suzuki Takayuki, Theatre Products, Nine and Double Standard Clothing -- in creating six-piece capsule collections for the Japanese chain and its 850 stores worldwide.

The first capsule, by Costello Tagliapietra, will hit stores April 21, with Charlotte Ronson following May 5 and Vena Cava landing May 12. Each piece is priced at $29.99 and will only be available until May 21.

"This is our anniversary of first working with Uniqlo last year," Robert Tagliapietra told StyleList. "We were intrigued by creating this capsule under the moniker of T-shirt dressing. It was an interesting exercise," he added because it is so different from the kinds of clothes he and partner Jeffrey Costello usually make.

Courtesy photo.

The resulting dresses are inspired by the high-end Costello Tagliapietra collection. "There's an asymmetric draped dress like one we have in our Spring 2010 collection. There's one with a cinch waist made from ties that creates this pleating that was inspired by a jacket we did several seasons ago," Tagliapietra shared.

"It makes sense for us to work with Uniqlo -- they're very purposeful about quality," he continued. "The clothes they create are mass, but cared for. It's inspiring us about how we could operate in the future."

We can hardly wait.