Wow, I'm oblivious to pop culture...well, kind of

My Merionite assignment (rough draft due on Friday) is to write an article about musicians who lip sing and why they do it and is it common. I don't know of any that do it but I can guess: Britney Spears, Ashlee Simpson (well, this we all know about), erm...I don't know who else. To those of you who do know, please help me. I have NO clue. I'm going to research online but they probably don't have a list of all of the popstars that do it. Either way, help is appreciated.

In need of help,
Adri