Mr. Imperium

Mr. Imperium UK title You Belong to My Heart is a 1951 romantic musical drama film made by MetroGoldwynMayer, starring Lana Turner and singer Ezio Pinza. It was directed by Don Hartman who cowrote the screenplay with Edwin H. Knopf, based on a play by Edwin H. Knopf. The music score is by Bronisaw Kaper. Lana Turners singing voice was dubbed by Trudy Erwin.

In Italy in 1939, a European man calling himself Mr. Imperium uses a ruse to meet an attractive American woman, Frederica Brown. He eventually is revealed to be Prince Alexis, an heir to the throne and a widower with a sixyearold son. He nicknames her Fredda, so she calls him Al.When his father becomes gravely ill, he must rush to be with him, but asks prime minister Bernand to deliver to Fredda a note of explanation. Bernand instead tells her the prince is gone for good, that this is his usual method of seducing and abandoning women. ........

Source: Wikipedia