The Edge, Bruce Springsteen, Paul McCartney and many other stars are in a documentary about Glen Campbell's farewell tour called I'll Be Me.
The pop-country legend was diagnosed with advanced Alzheimer's disease in 2011. The film shows live performances from his Goodbye Tour along with moments from his career and battle against the disease.
The Edge shares his admiration for the singer, who continued to perform despite his health problems: "The audience being there somehow triggers his ability to access that other part of his brain, which is incredible."
I'll Be Me, directed by James Keach, won the Grand Jury Prize at the Nashville Festival and will be in theaters on Oct. 24.