Instructables user sewlikemymom wrote up a tutorial for her shirred skirt made from an old t-shirt:

The Shirt Skirt is the best skirt you’ll ever own! It’s shirred waistband allows has plenty of give and allows the wearer to be comfortable at all time. They’re perfect for when you’re pregnant, they’re perfect for after you have the baby. They’re perfect if you change size or shape or hate your clothes. They’re just simply PERFECT. Comfortable, casual, and cheap.

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