It has been posted on the forum before, that Cecilia will release a new CD with Villazon called Treasures of Belcanto. I removed the comment, cause it was mostly wrong.
Cecilia WILL be featured on that album, prerelease on October 2nd, though :
Péchés de vieillesse, Vol. III: Tirana pour deux voix (Les amants de Séville) 4:28 Rolando Villazón, Cecilia Bartoli, Orchestra del Maggio Musicale Fiorentino & Marco Armiliato Treasures of Bel Canto
You can be the happy owner of that duet using Apple's iTunes Store -:).