!!1939 version
* ActingForTwo: Richard Greene plays both Sir Henry and Sir Hugo (even though Hugo is supposed to look like Stapleton the producers thought this would spoil the movie.)
* BillingDisplacement: This the only Sherlock Holmes film where the actors playing Holmes and Watson did ''not'' get top billing. Richard Greene, the actor who played Sir Henry, got the top bill. Creator/BasilRathbone got second billing and Nigel Bruce got ''fourth'' billing.
* PlayingAgainstType: Creator/BasilRathbone was best known for playing villains before he was cast as Holmes. Sadly, however, playing Holmes would doom Rathbone to typecasting ''again'' as he could never be associated with anything but Holmes after this.

!!1978 version
* ActingForTwo: Creator/DudleyMoore plays Watson, Mr. Spiggot, Mrs. Ada Holmes and Piano Player.
* TheCastShowoff: Creator/DudleyMoore plays the piano in this film. In real life, Moore was an accomplished concert pianist, and often on movie sets would entertain the cast and crew by playing the piano.
* CreatorBacklash: Creator/TerryThomas described this as "the most outrageous film I ever appeared in...there was no magic...it was bad !".

!!1982 serial
* CreatorBacklash: Creator/TomBaker himself came to consider his performance a failure saying: "I couldn’t lift the character into that special world that makes Holmes so funny and fascinating." He later claimed that Creator/TheBBC apologised for both the production and his performance.
* NeverWorkWithChildrenOrAnimals: Creator/TomBaker said of the titular hound:
-->He didn't want to harm Nicholas Woodeson, who was playing Sir Henry Baskerville. In fact, the bloody dog had fallen in love with Nicholas. Someone had the notion of hiding sausages under the lapels of Nic's dinner jacket, but it was of no use: The dog actually appeared to be blowing kisses at Nic. And then, a member of the camera crew suggested that, 'why didn't we throw Nic at the dog, and then run the film backwards?' Nic Wilson was not amused, but I was. I laughed so much, I hoped that the joke was what I'd been waiting for all these years before I died.

!!Other adaptations
* ActingForTwo: The 1981 Russian tv miniseries has the same actors who portray Jack Stapleton and Laura Lyons also portray Sir Hugo and his victim in the flashbacks.
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