British author and screenwriter J.K. Rowling poses upon arrival to attend the UK premiere of the film 'Fantastic Beasts: The Crimes of Grindelwald' in London on November 13, 2018. (Photo by Tolga AKMEN / AFP)
(Photo: TOLGA AKMEN/AFP via Getty Images)

J.K. Rowling is threatening to take legal action against a 'Harry Potter' fan on social media.

The author of the billion dollar book series budded heads with Wizarding News, a fan page which operates via X, formerly known as Twitter.

Rowling, 58, is fighting disturbing claims that she has an estranged daughter and grandchild. The fantasy writer isn't taking the rumor lightly, quickly rejecting the claim and firing back.

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"Reminder that JK Rowling's eldest daughter (the one with whom she was famously pregnant while writing Harry Potter) changed her last name to literally get away from Rowling, and moved to Portugal," the post alleged on X.

"Could somebody who isn't blocked by this account tell them this is untrue in all respects, as I suspect they already know," the writer responded Wednesday.

"Lying about my kids is a new low, even by this website's subterranean standards," Rowling fired back.

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The mother of three didn't stop there. She also addressed the inconsistencies of the user's claims, fiercely explaining that should the user refuse to "retract" the statement or "apologize," they'll be hearing from her lawyer.

"You've published easily disproven and damaging falsehoods. Should we go to legal proceedings, you will need to show why, in spite of being told the truth, you neither retracted nor apologized," she started.

"In the absence of any such retraction and apology, the next communication you receive will be from my lawyer."

Aside from being known for her magical book series, that has since been turned into blockbuster movies, she is often reported for offensive rhetoric.

She recently criticized Sky News on X following their recent report of a trans person who was jailed for murder known as the "cat killer," for referring to them as a "woman" without clarifying that the person was transgender.

She tweeted: "I'm so sick of this s****. This is not a woman. These are #NotOurCrimes."