This undated publicity photo released by the Sundance Institute shows, from left, Jo Lawry, Judith Hill and Lisa Fischer in a scene from the film, "Twenty Feet From Stardom," included in the US Documentary Competition at the 2013 Sundance Film Festival. (AP Photo/Sundance Institute, Graham Willoughby)

Associated Press
This undated publicity photo released by the Sundance Institute shows, from left, Jo Lawry, Judith Hill and Lisa Fischer in a scene from the film, "Twenty Feet From Stardom," included in the US Documentary Competition at the 2013 Sundance Film Festival. (AP Photo/Sundance Institute, Graham Willoughby)
This undated publicity photo released by the Sundance Institute shows, from left, Jo Lawry, Judith Hill and Lisa Fischer in a scene from the film, "Twenty Feet From Stardom," included in the US Documentary Competition at the 2013 Sundance Film Festival. (AP Photo/Sundance Institute, Graham Willoughby)