Rock-and-roll king Chuck Berry collapsed at a Chicago concert Saturday night and had to be helped off stage. Berry suddenly slumped head-first onto his keyboard mid-performance and didn't move for several minutes. Promoters said he was suffering from nothing more than exhaustion, but the rocker is pushing 85. The author of classics Johnny B. Goode and Roll Over Beethoven was "real confused," a local cop told the Chicago Sun-Times. He re-emerged later in the concert to tell his fans he didn't have the strength to continue. He appeared to have problems right from the start of the performance, according to witnesses. He was not taken to a hospital. (More rock and roll stories.)