This film was shot on the lavish sets created for Phantom of the Opera (1943) 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 (1925) starring Lon Chaney, and this extraordinary set still exists on the Universal Studios lot. It is the oldest surviving movie set in the world.
In the original trailer Susanna Foster, the star of Phantom of the Opera (1943), was given top billing. In the film itself, Boris Karloff is given top billing.
In the rehearsal sequence in which Angela loses her voice at the sight of Dr. Hohner, she closes her mouth a split second before the playback of her voice stops.