Previews were originally scheduled to begin Dec. 27, 1974 and were pushed back to Dec. 31 Opening night was originally scheduled for Jan. 8, 1975, but was pushed back when the production went on hiatus during previews (Jan. 9 - 13) for additional rehearsal. During previews, the musical's composer/bookwriter John Phillips, who also played the lead role, decided he should replace himself with Dennis Doherty, who was originally playing Dr. Bomb.