https://www.metv.com/stories/john-ritter-was-a-barrel-of-laughs-during-his-time-guest-starring-on-the-waltons

As an actor, Ritter was known for his work in television shows like Three's Company.

Series creator Earl Hamner Jr. was anxious to learn his family's opinion of The Waltons (https://www.metv.com/stories/series-creator-earl-hamner-jr-was-anxious-to-learn-his-familys-opinion-of-the-waltons)

"What would they think of a character portraying them week by week, often in stories based on their experiences in life or their personalities?”