week leave from "Bye Bye  Birdie" to film the shows pilot episode. During his absence,  understudy Charles Nelson Reilly (qv) filled in. When Van Dyke  left "Bye Bye Birdie" for good in April of 1961, he was succeeded by  the future host of _"Match Game, The" (1962)_ (qv),  Gene Rayburn (qv). Van Dyke was so nervous about filming the pilot  that he developed a cold sore on his upper lip, requiring additional  makeup to cover it up, and he admits he cannot recall President  Kennedy being inaugurated on the same day the pilot was filmed.