After Kelly Osbourne (left) made some unkind comments about former friend Christina Aguilera, Aguilera struck back. "She must have a crush on me because every five minutes she's saying something about me," Aguilera told Q Magazine. "I did see her at a club and said, 'Look, what is your problem?' And she had nothing to say. If you're going to talk sh** about me, do it to my face, because if you don't back it up you're just talking out of your ass." Classy.