Rehearsal Diary:. It’s often been said that 50% of acting is reacting. But tonight it approached nearer to 100% as we blocked the song “The Oldest Established.” What am I supposed to do for 2 or 3 minutes while I’m pushed around the stage by a chorus that sings my name over and over again? More and more I find myself angry at the original actor who played Nathan Detroit: why did he have to sing so badly that the authors cut nearly all of his opportunities to sing?