Actually, that's an old picture! I recognized those jeans from her "mom jeans" faux pas a few years ago. I googled Jessica Simpson mom jeans and actually that's a pic from 2009, and she's on stage there in concert. There are others that go with it.
But, I have no doubt she'll be there soon and maybe she already is. The pics I saw a couple of weeks ago she seemed to have slimmed down a lot since having the baby.