An upscale London restaurant had its windows smashed days after the owner was attacked online by trans-rights activists for helping “Harry Potter” author J.K. Rowling raise money for Ukraine.

Restaurateur James Chiavarini, 42, had first complained last week about the online attacks that followed Rowling sending him “massive thanks” for helping collect more than $23,000 for her war charity by hosting her at a fundraising dinner.

“The week I get harassed by evangelical TRAs [trans-rights activists], my restaurants get anonymous & generic bad reviews by trolls with similar pseudonyms,” Chiavarini noted last Wednesday.

“All due to helping raise money for Ukraine with the lovely JK Rowling and Suzanne Moore,” he said, with the latter a UK journalist who was forced out of The Guardian after uproar about her writing on transgender issues.

He also shared a series of one-star reviews accusing his restaurants of being unwelcome to trans diners.

Then on Friday, he posted a picture of shattered glass outside the front door of one of his establishments, Il Portico on London’s swanky Kensington High Street.

“In the same week as the online accusations of being homophobe for sticking up for JK Rowling and Suzanne Moore, followed the fake bad reviews, now someone has smashed in the windows at portico and ransacked the place,” he said.

“Could obviously be a coincidence, but what a few days!” he wrote.

Later the same day, he stressed that the glass was tempered and had been smashed from the outside as he noted that he had “stirred up a real hornets nest” with his tweet.

“The organized pile on from extremist TRAs is real for everyone to see,” he wrote.

“They have slandered my business and my character with false accusations in an attempt at vengeance because I (proudly) stand with Suzanne Moore and JK Rowling, both of whom I admire and respect greatly.

“The ransacking of my business happened the same week as the pile on,” he said.

Still, he conceded, “As things stand, it is impossible to prove that the two are related. I suspect that I will never know for sure. For now, there is no hard evidence, only a coincidence.”

His messages received a flurry of support online, with many saying they planned to travel to London just to support his businesses.

Chiavarini wrote, “The outpouring of love for a silly old-fashioned restaurant like mine is truly a joy to behold. I thank each and every one of you for your kindness and well wishes. God bless you all.”

Rowling’s cancel-culture backlash started in June 2020 when she sarcastically responded to an article about “Creating a more equal post-COVID-19 world for people who menstruate.”

“’People who menstruate,’” she tweeted snarkily. “I’m sure there used to be a word for those people. Someone help me out. Wumben? Wimpund? Woomud?”

Since then, she has reported alarming attacks calling for her to be canceled — and even death threats.