I've been wanting to try this idea, but didn't have a shirt to use. Then I realized this shirt had holes around the stomach -- probably from me trying to zip my fleece jacket up over my big belly.
I went to the fabric store, bought some black fabric for the waistband and skirt, and some purple to blend with the shirt. The purples aren't quite the same, but with the black in the middle, you can't tell.
I don't have a serger, but that would have been immensely helpful with this project. If I do much more with knits, I might have to start looking into one.
First, I sewed the purple strip onto the black strip at the bottom. Then I folded the whole thing in half and sewed it to make a tube. I planned to put the seam in the center back.
Then I found a shirt with an empire waist and cut my old shirt at about the same level.
Then, I decided I wanted a waistband and cut about 3" off the top of the skirt. Then, I evenly gathered the skirt into the waistband and sewed the skirt to the top.
I'll hem it tomorrow. I've noticed that these long dresses are in. I'm not so sure how I feel about that because they are so incredibly impractical. At least they're not as full as other long dresses I've worn.