Potterheads now know the reason why J.K. Rowling didn't reunite with the cast for the upcoming HBO Max Harry Potter reunion.

According to Entertainment Weekly, the famed author was invited to participate in the reunion special but her team believed that the archived footage from a 2019 interview on the Warner Bros. Studio Tour London would be sufficient enough. The report noted that Rowling's clips were "used sparingly" in the feature and that she primarily commented about the first of eight films in the franchise.

The Harry Potter 20th Anniversary: Return to Hogwarts will focus on the legacy of the films and not so much the books that Rowling penned. Insiders told the outlet that Rowling's controversy surrounding her past statements about trans people did not play a part in their decision to not have the Harry Potter creator participate in the discussion.

Despite Rowling's claims that she is not transphobic and that "trans lives matter," she has shared TERF (Trans-Exclusionary Radical Feminists) ideology over the years. The harmful rhetoric of the movement believes that trans women are not women.

"If sex isn’t real, there’s no same-sex attraction. If sex isn’t real, the lived reality of women globally is erased. I know and love trans people, but erasing the concept of sex removes the ability of many to meaningfully discuss their lives. It isn’t hate to speak the truth," she tweeted in 2020.

Last year, Rowling released her fifth book in her "Cormoran Strike" series, "Troubled Blood," under the pseudonym Robert Galbraith. The book followed the fictional life of a cisgender man who dressed up as a woman to kill women.

Harry Potter stars Daniel RadcliffeEmma Watson and Rupert Grint publicly spoke out in defense of transgender people.

Harry Potter 20th Anniversary: Return to Hogwarts premieres exclusively via HBO Max on Jan. 1.

Popular Child Stars From Every Year

Below, Stacker sifted through movie databases, film histories, celebrity biographies and digital archives to compile this list of popular pint-sized actors from 1919 through 2021.