Michael Jackson's Single "This Is It" Debuts

It's a big day for Michael Jackson fans, as the King of Pop's last single, "This Is It," debuted online last night. The single was to be part of Michael's comeback effort, which also included a series of concerts in London, also called the "This Is It" tour.

It's now streaming live from Michael's official site to promote the MJ rehearsal footage movie, This Is It, which hits theaters Oct. 28.

Listen to the new song below: