La Femme en homme (1931)
Directed by Augusto Genina

Film Synopsis

Unintentionally, a young woman sends a photograph to her grandfather in which she is dressed up as a man.  So as not to disappoint the old Duke, who is desperate to have a male heir, the woman must keep up the deception that she is a man, until the day when she must meet a princess and her son.  The woman falls in love with the handsome prince and in the end has no choice but to reveal her true identity...