Teen pop star Miley Cyrus had a scary moment during her show in Sydney, Australia Friday night when a woman jumped on the stage and grabbed the singer from behind.  Footage of the incident has been posted to YouTube, watch the clip below (the woman jumps onstage around the 3:53 mark).  Cyrus' security personnel were immediately on top of the woman, and Cyrus was obviously not hurt, but she was quite stunned, backing away saying "Oh My God!," into her microphone a couple times before security rush her offstage.