The Strange Case of Dr. Jekyll and Miss Osbourne (1981)

The film takes place before, during and immediately after the engagement party of Dr.Henry Jekyll and Miss Fanny Osborne, attended by numerous highly respectable guests (a general, a doctor, a priest, a lawyer), the last of which informs the company that a child has been murdered in the street outside. While the others watch a young dancer perform, Dr.Jekyll instructs the lawyer to alter his will, leaving everything to a certain Mr.Hyde. Shortly afterwards, the dancer is found murdered, and the guests realise that one of their number must be a maniac with a prodigious sexual appetite...