JK Rowling has posted an essay about signatories 'motivated by fear' after Harry Potter stars signed a pro-trans open letter. The author, 59, took to social media this weekend to state that 'nobody sane believes, or has ever believed, that humans can change sex, or that binary sex isn't a material fact'. Paapa Essiedu, who has been cast as Severus Snape in the upcoming series, was one of several signatories of the letter addressed to film and TV industry bodies encouraging them to support the trans community.