Author JK Rowling is an executive producer on the series, which HBO says will be a “faithful adaptation” of her books.
Some cast members have spoken about facing criticism for taking part from those who are opposed to Rowling’s views on trans rights.
Lithgow recently told the New York Times, external he almost pulled out of playing Dumbledore over the backlash.
“Every interview I will ever do for the rest of my life, this will come up,” he said.
Speaking to Deadline, external last year, Hagrid actor Frost said he did not agree “in any way” with Rowling’s views on the matter.
“She’s allowed her opinion and I’m allowed mine, they just don’t align in any way, shape or form.”
Last year, Essiedu was one of more than 400 actors to sign a petition calling for the UK entertainment industry to protect the trans community.
Rowling responded by saying she would not and could not fire actors who disagreed with her. “I don’t believe in taking away people’s jobs or livelihoods because they hold legally protected beliefs that differ from mine.”
Meanwhile, Essiedu has told the Sunday Times, external he has received death threats from racist trolls who think a black actor shouldn’t play Snape.
Bloys told Variety the producers had installed “serious security” on set as a result of such threats.
“With all actors on any kind of big IP shows – and this is obviously one of those where you’ve got passionate fans, people with a lot of opinions – it can get scary in places,” he said.
