Although he had been appearing in motion pictures for 25 years, this 1944 release was Boris Karloff's first film in color.
In the original trailer Susanna Foster, the star of Phantom of the Opera, was given top billing. In the film itself, Boris Karloff is given top billing.
This film was shot on the lavish sets created for Phantom of the Opera in an attempt to recoup the large budget of that film. The opera house set had been built for the original The Phantom of the Opera starring Lon Chaney, and this extraordinary set still exists on the Universal Studios lot. It is the oldest surviving movie set in the world.