The film's opening credits include special participation by Basil Rathbone and Boris Karloff. Both of these actors were long since dead, having died in the late 1960s (Rathbone in 1967 and Karloff in 1969), but they appear in this film in clips from real films that they had each starred in with Vincent Price: Rathbone in Muralhas do Pavor (1962) and Karloff in O Corvo (1963).
The final film that Vincent Price made for American International Pictures after a collaboration that began 14 years earlier with O Solar Maldito (1960).
During the film's last scene and over its closing credits, it is Vincent Price whose singing voice is heard.
Peter Cushing dresses up as Count Dracula in this film, an in-joke reference: he frequently played Doctor Van Helsing in Hammer Films' "Dracula" films.
The film's scenes shown at the costume party at Oliver's house as a tribute to Paul Toombes (Vincent Price) are from an actual film that Price starred in, O Poço e o Pêndulo (1961).