John Lithgow is opening up about about joining HBO’s Harry Potter series where he will take on the role of Albus Dumbledore.

Deadline broke the news that Lithgow was posed to portray the headmaster of the wizarding school Hogwarts in the TV series adaptation of J.K. Rowling’s fantasy novels.

“Well, it came as a total surprise to me,” Lithgow told Screen Rant in an interview. “I just got the phone call up at the Sundance Film Festival for yet another film, and it was not an easy decision because it’s going to define me for the last chapter of my life, I’m afraid. But I’m very excited.”

He continued, “Some wonderful people are turning their attention back to Harry Potter. That’s why it’s been such a hard decision. I’ll be about 87 years old at the wrap party, but I’ve said yes.”

Dumbledore was portrayed by the late Richard Harris and Michael Gambon in the Harry Potter movie franchise. Jude Law played a younger version of the character in the Fantastic Beasts prequel films.

The Harry Potter TV series, which will be filmed at Warner Bros Studios Leavesden where the movies were shot, is slated to debut on HBO in late 2026 or early 2027.

Designed to run over a decade on TV, the Harry Potter series comes from writer/showrunner Francesca Gardiner and director/executive producer Mark Mylod.

Casey Bloys, Chairman and CEO of HBO and Max Content, at the time of the original announcement called the show a “faithful adaptation” of J.K. Rowling’s novels which will “dive deep into each of the iconic books.”