Cheryl : She punched a toilet attendant in the face, in self defence. Then she got called a racist because the woman was black... And the fact that people still call her racist even though her husband was black
Demi : She punched her backup dancer in the face, then went to rehab for self-harming.
Justin : Too many to choose
Carrie really hasn't had one.
But I guess, when she came out in support of same-sex marriage and had quite a strong opinion on it.. a lot of Bible humpers freaked and I even remember several radio stations had "Bash Carrie Hour"
I would say her most controversial moments were the Salvia incident, the TCA ''pole dance'' and the CBT/WOMH videos. (Well the the videos, and the TCA performance were more controversial in prude America than anywere else. lol)
Kelly doesn't have many shocking or controversial moments.. the My December/Clive Davis thing is probably her biggest controversy. Then that tweet about Ron Paul last year