A spokesperson for Delsener said in a statement that Delsener and Millo had "mutually agreed" to cancel the event, which was to have been Millo's solo debut at Carnegie.
"As the repertoire took shape," the statement read, "Mr. Delsener anticipated a more contemporary crossover program of songs to appeal to a broad audience while Ms. Millo indicated that her fan base was primarily expecting a program of a more classical nature."
Delsener is one of New York's top concert promoters, responsible for a series of massive outdoor events and other rock shows over several decades. When the Millo event was announced in August, he said in a statement that he had been wowed by Millo's performance as Tosca at the Metropolitan Opera and declared her "the greatest living soprano in the world right now."
Pianist Ken Noda was to have accompanied Millo. The program, according to a press release in August, was to include "classical Italian music by Puccini, Verdi, Donizetti, and Bellini, as well as Neapolitan songs, a rare aria by Handel, and works by such composers as Brahms, Mahler, Donaudy, and others."