There are two Mystery Guests in this 1970 episode of the syndicated version of What's My Line? The first one is Clayton Moore in his Lone Ranger garb. The last one is Shelley Winters, who was plugging the Broadway show about the Marx Brothers, Minnie's Boys. The show opened to crippling reviews on March 26, 1970 (though you'll hear Shelley claim most of the reviews were good) and it closed May 30, 1970. This episode was taped on April 16 and Minnie's Boys was probably gone from The Great White Way by the time most of America saw this.