Scooby-Doo
The first episode of "Scooby-Doo, Where Are You!" "What a Night for a Knight" debuted on the CBS network Saturday, September 13, 1969. The original voice cast featured veteran voice actor Don Messick as Scooby-Doo, radio DJ Casey Kasem (later host of radio's syndicated "American Top 40") as Shaggy, actor Frank Welker (later a veteran voice actor in his own right) as Fred, actress Nicole Jaffe as Velma, and musician Indira Stefanianna Christopherson as Daphne. Scooby's speech patterns closely resembled an earlier cartoon dog, Astro from "The Jetsons" (1962–63), also voiced by Messick. Seventeen episodes of "Scooby-Doo Where are You!" were produced in 1969–70. The series theme song was written by David Mook and Ben Raleigh, and performed by Larry Marks.
Scooby-Doo
In 1972, new one-hour episodes under the title "The New Scooby-Doo Movies" were created; each episode featuring a real or fictitious guest star helping the gang solve mysteries, including characters from other Hanna-Barbera series such as "Harlem Globetrotters", "Josie and the Pussycats" and "Speed Buggy", the comic book characters Batman and Robin (later adapted into their own Hanna-Barbera series, "Super Friends", a year later), and celebrities such as Sandy Duncan, The Addams Family, Cass Elliot, Phyllis Diller, Don Knotts and The Three Stooges. Hanna-Barbera musical director Hoyt Curtin composed a new theme song for this series, and Curtin's theme would remain in use for much of "Scooby-Doo's" original broadcast run. After two seasons and 24 episodes of the "New Movies" format from 1972 to 1974, CBS began airing reruns of the original "Scooby-Doo, Where are You!" series until its option on the series ran out in 1976.