Buster in his role as King Sextimus for Once Upon a Mattress, a musical retelling of The Princess and the Pea. I like this mention of it on the Wiki page: “Keaton warmed up to the cast of younger actors, dispensing grandfatherly advice and chocolate freely.” His wife, Eleanor, was in the chorus as well.
I was also pretty excited to hear that he was in it since we actually performed it when I was in high school. It’s not as adult-themed as it sounds, although I did have to hear plenty of “Do I want to buy tickets for WHAT?”
Our high school did this play as well. King Sextimus was the perfect role for Buster!
By the by, no one happens to know if there’s a recording of it anywhere, do they?