The club have officially said they will not be adding a 3rd star.
Edit : Sry, Not official.
http://www.vecchiasignora.com/topic/262843-la-repubblica-in-caso-di-scudetto-la-juve-non-metter-la-terza-stella-sulle-maglie-una-forma-di-coerenza-per-la-loro-contabilit-parallela/