With a career that spanned 50 years on the silver screen, John Wayne‘s legacy expanded far beyond his films — and he even made an unusual impact on TV’s beloved Gunsmoke. The incident happened on September 10, 1955, right before the very first episode of the Western series aired on CBS. And when it happened, the entire cast of the show, who were all gathered together to watch, couldn’t believe what they were seeing on TV.

When Gunsmoke premiered, it was an immediate hit, and remained that way for many years. This success was not just due to the phenomenal cast, which included James Arness, Amanda Blake and Dennis Weaver, but also because it was already very popular as a radio drama starring William Conrad as Marshal Matt Dillon, protector of Dodge City, Kansas.