'Undercover Angel' singer Alan O'Day dead at 72 WESTWOOD, Calif., May 20 (UPI) -- Singer-songwriter Alan O'Day died of cancer at his home in Westwood, Calif., his record label said. He was 72. O'Day, surrounded by members of his family and friends, died Friday. "Alan was a generous man who gave his heart and soul to the music industry," 1st Phase Records said in a statement to UsMagazine.com. O'Day wrote and performed "until his last days," the statement said." The type of cancer he suffered and how long he battled it were not disclosed. O'Day, best known for writing and singing the 1977 song "Undercover Angel," also wrote the 1970s hits "Train of Thought," "Rock and Roll Heaven" and "Angel Baby" and dozens of songs for the 1980s animated television series "The Muppet Babies," UsMagazine.com said.