The Millionaire Uncle.

The first Austrian feature film. Count Hubert Marischka has a passion for actress Marietta Weber, so when his wife goes to visit her mother, he invites the lady to join him at home and a masquerade. When his uncle comes to visit, he mistakes her for his nephew's wife and they all go to the costume party. Little does Marischka suspect that his wife has actually gone to a hotel and she, too, will show up in fancy dress.