Here's everything to know about HBO's 'Harry Potter' series, which may have recently cast its new Dumbledore After seven books, eight movies, one play and a whole spin-off series, Harry Potter is debuting on the small screen for the first time.

HBO’s Harry Potter series casts John Lithgow as Dumbledore, and the actor responds to concerns that he’s an American undertaking the role.

It seems John Lithgow spilled the (Bertie Bott's Every Flavor) beans about his involvement in HBO's in-the-works 'Harry Potter' series. 'A total surprise to me,' he says.