Summary from Wikipedia

Ivan "Ivica" Šerfezi started singing in dance halls, and his first real success was a duet with Domenico Modugno at the Maksimir Stadium, Zagreb (Modugno had a worldwide hit song, "Volare"). In the 1960s and the 1970s Šerfezi made many tours throughout Yugoslavia, East Germany, as well as the Soviet Union, and his concerts filled up 150 venues.