In 1969, Caballé appeared at the Arena di Verona in a Jean Vilar production of Verdi's "Don Carlo". She was Elisabetta of Valois in an all-star cast including Plácido Domingo and Piero Cappuccilli. In the same period she also appeared in recital at the Teatro Corallo in Verona. In 1970, Caballé made her official debut at La Scala in the title role of "Lucrezia Borgia". She appeared as Leonora in Philadelphia, and returned to the Met as Amelia in a critically acclaimed production of Verdi's "Un ballo in maschera" with Domingo as Riccardo, and Reri Grist as Oscar.