Host: Donald O'Connor --Donald O'Connor dances with the Louis DaPron dancers --Don Knotts (comedian) - appears, in a comedy sketch, as a bashful after-dinner speaker --Buddy Greco (singer-pianist) --The Wellingtons (singing group) - perform with Donald O'Connor --Mary Costa (Metropolitan Opera soprano, formerly a TV pitchwoman) --Jack Olvin and Yvonne Wilder (comedians, spoofing ""Hamlet) --The Pompoff Thedy musical clowns (Vaudeville comedians) --Francis Brunn (juggler) Note: Buddy Hackett was originally scheduled to appear on this episode.