…in appeared on Thursday’s episode. But too sad for the fans, Justin Bieber was shot dead in this episode, killed in a shooting scene. Bieber played a troubled teen in the episode called “Targets of Obsession.” Billboard Hot 100 notches 1,000th No. 1 single: From Ricky Nelson to Lady Gaga Friday, February 18, 2011 11:31 AM Lady Gaga has snagged a piece of pop music history in landing the No. 1 spot on the Billboard Hot 100 this week with her ne…