" Indeed, [Jimmy] Dean believed in Rowlf so completely that he would sometimes genuinely break up when Rowlf delivered one-liners, laughing so hard that he was unable to sing. "I treated Rowlf like he was real, but he WAS real to me," Dean said, "and I think that's one of the reasons he made such an impression on everyone. "

― Brian Jay Jones , Jim Henson: The Biography