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."

Cillian Murphy’s name has come up a lot, with rumors that he will play either Lord Voldemort or Professor Quirrell. “I May Destroy You” alum Paapa Essiedu is strongly rumored to be playing Severus Snape, while Ted Lasso’s Brett Goldstein has been named as a possibility for portraying Rubeus Hagrid.

Lithgow will join showrunner Francesca Gardiner and series director Mark Mylod for the upcoming series. No other cast members have been announced so far, but in September 2024, Warner Bros. announced an open casting call for Harry, Ron, and Hermione— aka future wizards who will be lucky to learn from Lithgow.