Katy Perry Surprises L.A. Crowd at Her Concert Film Screening, Leads Sing-Along and Q&A

Katy Perry made an unannounced appearance at a VIP IMAX showing of her concert documentary in Los Angeles, joining fans for the finale and a lively sing-along. She then sat for a Q&A with Billboard's Tetris Kelly, reflecting on her 91-show world tour that supported her album '143'. The screening marked the West Coast premiere of the film, which had debuted at the Tribeca Festival in June.