Radcliffe, 33, has now told Indiewire: “The reason I felt very, very much as though I needed to say something when I did was because, particularly since finishing Potter, I’ve met so many queer and trans kids and young people who had a huge amount of identification with Potter on that.
“And so seeing them hurt on that day I was like, I wanted them to know that not everybody in the franchise felt that way. And that was really important.
“It was really important as I’ve worked with the Trevor Project for more than 10 years.
“And so I don’t think I would’ve been able to look myself in the mirror had I not said anything. But it’s not mine to guess what’s going on in someone else’s head.”
Rowling was 'cancelled' after she responded to a story with a headline that read: “Opinion: Creating a more equal post-COVID-19 world for people who menstruate.”
She tweeted: “‘People who menstruate’. I’m sure there used to be a word for those people. Someone help me out. Wumben? Wimpund? Woomud?”
The writer went on to publish an essay online in which she claimed - as a domestic violence survivor - that she felt allowing trans people to use single-sex bathrooms and changing rooms could be "offering cover to predators".
At the time Radcliffe released a statement through LGBTQ suicide prevention charity The Trevor Project saying: “Transgender women are women. Any statement to the contrary erases the identity and dignity of transgender people and goes against all advice given by professional health care associations who have far more expertise on this subject matter than either Jo or I.
“To all the people who now feel that their experience of the books has been tarnished or diminished, I am deeply sorry for the pain these comments have caused you."
And other members of the cast have defended the writer.
The 81-year-old gay actor said: "There isn't one answer to all these trans questions."
The later Robbie Coltrane who played groundskeeper Hagrid, also defended the writer.
He said previously: “I don’t think what she said was offensive really. I don’t know why but there’s a whole Twitter generation of people who hang around waiting to be offended."
Watch: Harry Potter star Ralph Fiennes defends JK Rowling