Whoever said "blue and green should never be seen" clearly never spotted Katy Perry rocking a forest green dress beneath her dyed-blue tresses at the Yves Saint-Laurent Ready-To-Wear Fall/Winter 2012 show today for Paris Fashion Week. We're so used to seeing the "Part of Me" songbird in the brightest colors of the rainbow, we hardly recognize her in this dark ensemble (to match the B&W look she sported in Interview magazine, perhaps?), complete with leather jacket and boots. But does she pull it off? Yes. Now only one question remains — why didn't she join Diddy and Robyn for crepes?