New Harry Potter actor John Lithgow has weighed in on JK Rowling’s trans views, admitting he finds them “ironic and inexplicable”.

The actor is set to play the Hogwarts headmaster Dumbledore in the new HBO series adaptation of Rowling’s books, which has attracted controversy amid the author’s views.

Speaking at the Rotterdam Film Festival, Lithgow said he takes “the subject extremely seriously”.

“[Rowling] has created this amazing canon for young people and it has jumped into the consciousness of the society,” he added (via Variety). “It’s about good versus evil, kindness versus cruelty.

“I find her views ironic and inexplicable. I’ve never met her, she’s not really involved in this production at all. But the people who are, are remarkable.”

He added: “It upsets me when people are opposed to me having anything to do with this. But in Potter canon you see no trace of transphobic sensitivity. She’s written this mediation of kindness and acceptance. And Dumbledore is a beautiful role.”

Addressing calls for him to step away from the role, Lithgow explained: “It was a hard decision. It made me uncomfortable and unhappy that people insisted I walk away from the job. I chose not to do that.”

Last year, the actor admitted he was surprised by the backlash over his casting, revealing that he received a message from “a very good friend who is the mother of a trans child” about an op-ed encouraging him to step away.

“I thought, ‘Why is this a factor at all?’ I wonder how J.K. Rowling has absorbed it,” he told The Sunday Times. “I suppose at a certain point I’ll meet her, and I’m curious to talk to her.”

Rowling’s views have stirred controversy over the past few years, including her support of a Supreme Court ruling last year that the legal definition of a woman is based on biological sex.

The new HBO series will adapt each of the Harry Potter novels per season each across a decade, with newcomers Dominic McLaughlin, Arabella Stanton and and Alastair Stout set to play the roles of Harry, Hermione Granger and Ron Weasley.

Nick Frost will take on the role of Hagrid, while Paapa Essiedu will play Severus Snape, and Janet McTeer will portray Minerva McGonagall. Warwick Davis will reprise his role as Filius Flitwick from the original film series, and recently said the series will be “very faithful” to the books. Meanwhile, Hans Zimmer is set to compose the score.