Till the World Ends
Ke$ha ----> Britney Spears (???)
Also Hold It Against Me. Correct me if i'm wrong.
Gaga wrote and co-produced JLo's Hypnotico. I think it would be a hit if released as second single, or even a Gaga feat.
Such a good song. Also Invading My Mind.
Poor Leona almost got her hands some smash hits.
Kelly got a lot of 'second handed' hits