"Eres tú"; "It's You" is a song recorded by Spanish band Mocedades, written by Juan Carlos Calderón. It represented Spain in the Eurovision Song Contest 1973 held in Luxembourg placing second which was followed by a global success. The song below is sung by un cantante de Argentina. Se llama Justo Llamas. Justo toured the USA for several years doing educational concerts.
I encourage you to research the original singers & listen to that version as well.