Ed Sullivan inspired a song ("Hymn for a Sunday Evening") in the Broadway musical 'Bye Bye Birdie' (1960). Sullivan appeared as himself in 'Bye Bye Birdie (1963)', which would be released in early April 1963.
Edward Mulhare was starring since December 1961 in the Broadway comedy 'Mary, Mary' (1961), the longest-running non-musical Broadway play. Mulhare would remain with the production until July 01, 1963. The play was adapted into 'Mary, Mary (1963)'.
This episode celebrated St. Patrick's Day by having all three contestants and guest panelist Edward Mulhare born in Ireland, and the mystery guest from Irish descent.