Professor Bond is doing research on an island in the Java Sea when his son discovers the giant ape and befriends him, and together they fight to protect Kong from Dr. Who, who has sinister designs on the ape. Each episode consisted of a King Kong story, a Tom of T.H.U.M.B., then another King Kong story. 
Tom of T.H.U.M.B. is a gag cartoon about a secret agent and his oriental sidekick. Animage Pocket Data Notes credits MORI Yasuji and KANISHI Takao as either character designers or animation directors of the latter, differing from the credits for the King Kong portion of the show. 
This was the first cartoon TV series animated entirely in Japan expressly for American television. American sources state Rankin-Bass commissioned the work from Videocraft International; Japanese sources state it was produced by Videocraft/Toei Doga. 
(Source: AniDB)

King Kong - 00 1/7 Tom Thumb