Although playing an Irish American father and son, neither Danny Thomas nor Tom Bosley were of Irish background. Danny Thomas (born Amos Kairouz) was Lebanese American and Tom Bosley was Jewish.
Danny Thomas (who played Grandpa) was the producer of "The Andy Griffith Show" of which Ron Howard (Richie) played Opie Taylor.
Danny Thomas plays the father of Tom Bosley's character. In real-life, Thomas was only 15 years older than Bosley.
Howard Cunningham (Tom Bosley) states he is 47 years old. At the time, Tom Bosley was nearly 51 years old.
Ron Howard and Danny Thomas had worked together before when Ronny was five years old and playing Opie Taylor for the very first time on the Make Room for Daddy entry, Danny Meets Andy Griffith.