Al Pacino sings Sweet Baby Doll at Greek Theater LA

During intermission at the Chicago concert, Al Pacino came onstage with film crew while thousands of fans served as extras. Cameras were wheeled onstage on Friday night August 2, 2013 to film a scene from Pacino's upcoming movie "Imagine," in which he plays aging rock star Danny Collins. With coaching from the director, the crowd chanted the name of Pacino's character Danny as the 73-year-old actor walked on stage to sing "Sweet Baby Doll" in a black suit. The movie co-stars Michael Caine, Annette Bening and Jennifer Garner. "This is an improvisation," Pacino told the crowd. "You just came in and got it. That's not easy." Chicago's band members remained on stage to watch and clap along during the 25-minute filming.