In the Sign of the Gemini (1975)

It's 1930, and two record producers - Master Records and Onofon - are competing to sign a lucrative contract with the leading singer of the day, Dolores Rossi. The Director of Onofon, one Ulrik Ulvenstein, will stop at nothing to sign Ms. Rossi. When he kidnaps Anthon Master, he thinks it's in the bag. But he didn't count on Anthon Master having a twin brother, Benny - a straight-laced funeral director - who gets "recruited" to cover for his missing brother at the contract signing. As the deadline looms closer, Ulvenstein's dim-witted goons try to sort out why their hostage keeps reappearing at Ms. Rossi's ... and a befuddled Ms. Rossi wonders at the personality swings the Director of Master Records is exhibiting. But have no fear, there's always one way to tell twins apart...