There is a widespread rumor that in the German dub of the film, Dr Who has been renamed to Dr. Frankenstein. The reason for this is that in Germany, many classic Japanese giant monster movies were given an unique spin by inserting references to a certain Dr. Frankenstein, and explaining away many monsters as being his creations. In fact, the name Frankenstein often appeared in the title, despite no person named Frankenstein ever appearing in any of the films - his existence was merely alluded to. But in contrast to what the rumor claims, Dr. Who kept his original name in the film's German version. The title was, however, changed to the confusing-sounding "King Kong: Frankenstein's Son", which may have added to the myth.
The voice of Dr. Who is the legendary Paul Frees, the man of a thousand voices, who also voiced both Burgermeister Meisterburger and Grimsby in another Rankin/Bass production, Santa Claus is Comin' to Town.
Two costumes of King Kong were made. The arms of the first costume were very long, so Haruo Nakajima's hands did not reach those of the costume. He had to grasp onto sticks that were attached to the hands of the costume. He wore a second costume with shorter arms whenever they were shooting footage of King Kong battling other monsters.
This film was a live action tie-in to the animated TV series King Kong (1966), which was also produced by Rankin/Bass Productions, and not a sequel to King Kong vs. Godzilla (1962) (also produced by Toho and directed by Ishiro Honda) as is often suggested.
True to say the film has no actual connection to Dr Who - the Mad Scientist figure is called Dr Wu in the original. But he appears wearing the astrakhan hat and cape of the first Dr Who, William Hartnell, and is made up to look more than a bit like him....
In Spain the film has been re-released twice in cinemas (American version). At first, in 1977 -in all country- with the title 'Renace Y Ahora: King Kong Escapa' and after, in 2016, was a second re-release only in Barcelona (Phenomena) in 35 mm. copy and dubbed version for 1 day.