Haas met Tito in Paris, France, in 1937, a year after he had divorced his first wife, Pelagija "Polka" Belousova. In 1940, Haas travelled to Istanbul, Turkey, to deliver a passport to Tito, who was returning from a trip to Moscow, Soviet Union. Their relationship soon turned romantic, according to Tito's authorized biography, "The Loves of Josip Broz Tito." The couple married in 1940 and returned to Yugoslavia using aliases. They lived in Zagreb until the Invasion of Yugoslavia, when Tito moved to Belgrade, while Haas, who was pregnant with their only child, remained in Zagreb.