HBO's 'Harry Potter' TV show recasts all of the Hogwarts characters with new actors. See who's who in this cast guide.

HBO's "Harry Potter" television adaptation is slowly coming together, but we're still a ways out from actually getting it on our screens. That said, we are learning more and more as the months go on.

John Lithgow has said that he’s “very excited” to be joining the upcoming “Harry Potter” series as Albus Dumbledore, brushing off criticism that the role of the wizarding headteacher has been given to an American actor.