Who was the worst-dressed female star at the Grammy Awards?

Did Katy Perry not get the "buttocks and breasts" memo warning stars to be "adequately covered" at the Grammys? It certainly doesn't look like it!

While we didn't love the beading or the color of Perry's mint green Gucci gown, there's no denying that John Mayer is a lucky man. Jennifer Lopez also seemed to flout the dress code, covering the key areas with her leotard gown but also trying to show as much skin as possible. Trying a bit too hard, perhaps?Adele went in the other direction, covering TOO much skin in a cocktail dress that appeared to be made out of Grandma's curtains. And Beyonce didn't even bother to get dressed up — she showed up in a pair of black pants.