Lee Pace ("Pushing Daisies") and Linus Roache ("Law & Order") have also joined the pilot's cast.
As Playbill.com previously reported, the pilot will be written by Tony-winning playwright John Logan (Red) and directed by Academy Award winner Kathryn Bigelow ("The Hurt Locker"), who will also executive produce the series.
Previous reports said Langella (Frost/Nixon, A Man for All Seasons) would play the composer's father, Davis (God of Carnage) would play the composer's sister, and LuPone (Gypsy, Evita) would be cast as a Broadway diva. Roles for Sands (American Idiot, Journey's End), Pace and Roache were not clearly outlined.
A spokesperson for Tony winner Norbert Leo Butz confirmed to Playbill.com that the actor will play the lead role of the tortured composer.