Overview
Shazam! is a half-hour live-action television program that was produced for Saturday Mornings by Filmation (the studio's first non-animated series), based on the superhero Captain Marvel, now known as Shazam, of Fawcett Comics' comic book series Whiz Comics (now owned by DC Comics). The program starred Michael Gray as Billy Batson, a teenage boy who can transform into the superhero Captain Marvel, originally played by Jackson Bostwick and later by John Davey, by speaking the magic word "Shazam!" With his guardian "Mentor" (Les Tremayne), Billy travels the country in a 1973 Dodge Open Road motorhome, looking for injustices to resolve.
The show ran from 1974 to 1976 on CBS's Saturday morning lineup. From 1975 to 1977 it was known as The Shazam!/Isis Hour and included The Secrets of Isis, about an Ancient Egyptian superheroine resurrected in the body of a schoolteacher, as the second half of the hour.
Format
The Mentor character, as played by Les Tremayne, was unique to the TV series and did not originate from the Shazam! comics. His background, and the origin of his relationship to Billy, were never explained.
In later issues of the 1970s Shazam! comics meant to tie-in with the TV show, Billy's Uncle Dudley grows a moustache, drives Billy around the country in an RV, and tells Billy that the Wizard Shazam chose him to be Billy's "mentor", essentially turning Dudley into the comic book version of Mentor. The Mentor character has not been used since, although Uncle Dudley is shown driving a similar RV in the 2010s animated series Justice League Action.
From Wikipedia (CC BY-SA 4.0).