A Strong Blow (1967)

Kuba, a shy young man and his girlfriend Majka want to get married. Shortly before the marriage, however, a young woman appears in front of the registry office, who slaps the groom and accuses him of having promised her marriage and fidelity. The bride leaves the desperate Kuba, who decides to clear up this misunderstanding. It turns out he looks remarkably like Jonny Tomala, a successful crooner and guitarist. To prove his innocence, Kuba wants to show his fiancé the double at all costs. But with the music star swallowed up by the face of the earth, Kuba gets an offer to represent Jonny Tomala on a TV show.