Which artist recorded a song with Diddy that was in the number one position of the Billboard Year-End Hot 100 Singles of 2010?
Billboard Year-End Hot 100 singles of 2010:  At the number-one position was Kesha's "Tik Tok", which stayed atop the Hot 100 for nine weeks. Tik Tok:  The experience triggered the writing of the song which she later brought to her producer, Dr. Luke, who was then contacted by Diddy in hopes of a collaboration; he came to the studio the same day and recorded his lines and the song was completed.
Kesha