Bobby Byles

 played Fred, a man in the waiting room with father-to-be Darrin, in the second season episode, And Then There Were Three (1966).

Biography
Robert John Byles was an American actor, born on May 12, 1934 in Shreveport, Louisiana. He was the son of Robert John "Ross" and Madeline Byles. Byles was a 1956 graduate of Northwestern State University with a degree in Speech, and was prominent in the theatre department and other organizations. He was president of Alphi Psi Omega, [and] associate editor of NSU's yearbook, Potpourri. Byles was also in The Newman Club, an organization of Catholic Culture and Fellowship.

Byles was known for The World: Color It Happy (1967), War Is Hell (1962) and Death Valley Days (1952). He also appeared in The Guns of Will Sonnett (1969), Breaking Point (1964), Dr. Kildare (1963), and My Favorite Martian (1963).

Robert John Byles died on August 26, 1969, in Hollywood, California, of a heart attack. He was 35.

Source
Finch, Scout. Robert John "Bobby" Byles memorial on Findagrave.com. May 29, 2012. Retrieved on March 15, 2021, edited.