Hollywood veteran John Lithgow says he was unprepared for the backlash he received after agreeing to be part of the upcoming Harry Potter TV series.

Lithgow, 79, is cast as Hogwarts headmaster Albus Dumbledore in HBO adaptation of JK Rowling’s magical book series.

Lithgow, – who can be seen in cinemas in the Oscar-nominated Conclave – told the Sunday Times’ Culture magazine this week he was surprised to receive almost instant criticism because of the project’s ties to the Rowling, who has caused controversy with her advocacy for single-sex spaces and women’s rights, which have been viewed as anti-trans by some.

Showing some of the messages he received, he said: “I thought, why is this a factor at all? I wonder how JK Rowling has absorbed it. I suppose at a certain point I’ll meet her and I’m curious to talk to her.”

Asked if the comments he’d received had made him have second thoughts, he added: “Oh, heavens no.”

And after playing the late Roald Dahl in stage show Giant, Lithgow said he’s baffled that no one questioned his association with that children’s author because of his anti-Semitic comments.

“No one complained when I agreed to play Dahl, but I’ve received so many messages about JK Rowling. Isn’t that odd?” he said.

While undeterred by Rowling’s involvement, Lithgow did reveal that Dumbledore would likely be his final role.

“Of course, it was a big decision because it’s probably the last major role I’ll play,” he said.

It’s an eight-year commitment so I was just thinking about mortality and that this is a very good winding-down role.”

Rowling’s stance on women’s rights versus trans gender righrts was that the fore again this month after a UK Supreme Court decision that legally defined “woman” and “sex” as referring exclusively to individuals born biologically female.

Rowling celebrated the ruling online, prompting anger from many opposed to the ruling and her stance.

Actor Pedro Pascal, who starred in HBO’s Last of Us, in the past days has called for a boycott of all Harry Potter-related content including the upcoming series in response to Rowling’s involvement.

Pascal condemned Rowling’s stance as “awful disgusting SH-T” and “heinous LOSER behaviour” in a post on Instagram.

Rowling posted a series of social media posts in 2020 claiming that the existence of transgender people “erased” the “lived reality of women.”

Shortly after, Harry Potter film stars Daniel Radcliffe, Emma Watson and Rupert Grint issued statements opposing her opinions.

-with AAP