Katy Perry may be newly single, but she's certainly not letting her mood match the color of her hair. In fact, the "Part Of Me" songbird couldn't have looked any rosier at last night's MusiCares tribute to Sir Paul McCartney — mostly because she was rocking a giant pink flower on her head. "Tonights lewk is Petal Power themed," Katy tweeted shortly before the event, where she sang The Beatles' "Hey Jude" in tribute of MusiCares' "Person of the Year."