Per IMDB, Granny (Irene Ryan) "misinterprets a phone call from Cousin Pearl and believes Indians have attacked in Bug Tussle and have taken over Clampett land. In reality, there is a simple boundary dispute, and when Chief Running Wolf and Little Fox travel to Beverly Hills to settle the dispute with Jed, Granny prepares for an all-out Indian war and Mr. Drysdale goes to war to protect the Clampett fortune."
During what Granny processes as an all-out battle against an indigenous tribe, she prays that The Duke himself will show up and save the day.
Wayne shows up after the CBS sitcom's latest wacky plot line reaches its conclusion, only to get shamed by Granny: "Where was ya when I need ya, John?"
What's wildest is the visual of Wayne dressed more like Bear Bryant than the Western movie star of The Searchers and other revered films.
As the story goes, Wayne requested just one thing in return for appearing on the popular TV show: a fifth of Jack Daniels bourbon.
No word on whether or not a bottle of bourbon was exchanged for Wayne's intro of Gunsmoke's debut episode from way back on Sept. 10, 1955.
The Paul Henning-created series also starred Buddy Ebsen as Jed Clampett, Max Baer Jr. as Jethro Bodine and Donna Douglas as Elly May Clampett. Its use of "The Ballad of Jed Clampett" as its theme song offered a huge popularity boost to bluegrass music.