The Emmy-winning actor, hot off a SAG Award for "Conclave," said playing the Hogwarts headmaster would "define me for the last chapter of my life."

In an interview with Screen Rant, Lithgow said that he has accepted the role of the Hogwarts head wizard in HBO’s forthcoming series: “I’ll be about 87 years old at the wrap party.”

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.