In Bieber's second album, because of puberty, his voice was deeper than it was in his first album.[55] In April 2010, the singer discussing his vocals remarked, "It cracks. Like every teenage boy, I'm dealing with it and I have the best vocal coach in the world. [...] Some of the notes I hit on "Baby" I can't hit any more. We have to lower the key when I sing live."[56] Bieber guest-starred in the season premiere of the CBS crime drama CSI: Crime Scene Investigation, which aired on September 23, 2010. He played a "troubled teen who is faced with a difficult decision regarding his only brother", who is also a serial bomber. Bieber was also in a subsequent episode which aired on February 17, 2011, in which his character is killed.[57] Bieber performed a medley of "U Smile", "Baby", and "Somebody to Love" and briefly played the drums at the 2010 MTV Video Music Awards on September 12, 2010.[58] Bieber announced in October 2010 that he would be releasing an acoustic album, called My Worlds Acoustic.[59] It was released on November 26, 2010 in the United States and featured acoustic versions of songs from his previous albums, and accompanied the release of a new song titled "Pray".[60]