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.

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.

Lithgow's casting breaks tradition of British actors in Harry Potter, sparking debate. HBO's American casting decision opens more opportunities for diverse talent in series. Auditions for lead trio ongoing, with Paapa Essiedu as Snape and Cillian Murphy as Voldemort rumored.