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.

Is John Lithgow playing the new Dumbledore? Here's what he said in an interview and why people are speculating.