That is priceless, he's singing a line from Amy Winehouse's song - "Rehab".

I dont get it - what the hell has what she does got to do with him?! He's just fuelling the press fire.
I've said this before but I'll repeat it- CMAR is about Britney. Everybody knows that. He has been ad libbing what he sings along with certain gestures since the beginning and he will continue to do so in concert as long as he sings that song. It's part of his performance just like practically kissing his dancers and rubbing all over them. The press will continue to try and link Justin and Britney whether he ad libs during CMAR or not. I personally think it's hilarious.