In the second half of the 1970s, Kalatzis co-operated with composer Nikos Karvelas and in 1981 he released an album with the songs of Tolis Voskopoulos.
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His popularity began to increase and he had a productive collaboration with some of the most famous Greek composers of the period - Manos Loizos, Stavros Kougioumtzis, Giorgos Katsaros, Mimis Plessas, Giannis Spanos, and Tolis Voskopoulos.
His early career began with appearances in major nightclubs alongside well-established names in the Greek music scene, such as Tolis Voskopoulos, Makis Christodoulopoulos, Eleni Dimou and Giorgos Alkaios.