Oh, 40! You rascal, you. You get a hold of some people, like Irish singer-songwriter Sinead O'Connor, and you create a whole new person.
O'Connor, 44, was snapped at a concert in England last weekend, looking nearly unrecognizable from the svelte, shaven, classical beauty we remember from the late 1980s.
On the other hand, the Big Four-Oh is treating some stars just fine. Take a peek at our slide show and tell us who you think is the hottest female rocker north of 40.