ASHLEE SIMPSON not only has a new album coming out, but she's getting into the designer clothing biz! People.com reports that the younger Simpson sister is launching a collection of T-shirts for Wet Seal.

"I was inspired by so many fun, wonderful things as I was recording Bittersweet World and it's been great to carry through those inspirations into these new shirt designs," says Ashlee.

The new line of shirts, which will launch nationwide on April 22 -- the same day as her album -- features designs inspired by Ashlee's personality, sense of style and album artwork.

"I hope my fans love this album and rock out in these shirts!" says Ashlee.