Julia Quinn, known best for her best-selling book series "Bridgerton," which was turned into a Netflix show, is mourning the loss of her father, Steve Cotler, and sister, Violet Charles.

The author confirmed their tragic deaths in a post on Facebook. She detailed how they were killed on June 29 by a drunk driver who crashed into their car on a highway in Utah.

"I have lost my father and my sister. Because a catering company did not secure their load and canvas bags spilled onto the highway. Because a pickup driver thought nothing of driving while his blood alcohol level was nearly 3 times the legal limit," Quinn, 51, wrote. 

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"I have lost my father, and I don’t have my sister with whom to grieve. I have lost my sister Violet Charles Comics, with whom I had just finished writing a graphic novel. It was dedicated to our father," she continued.

"Bridgerton" author Julia Quinn lost both her father and sister in a car crash in June.  (Tamron Hall Show/ABC)

Steve was 77 years old while Violet, whose real name was Ariana, was 37. 

"It will still be dedicated to our father. It won’t be a surprise anymore, but I’d like to think he suspected we’d do it. He knew us so well. He was our dad," Quinn concluded.

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Violet’s service dog named Michelle was also killed in the crash. 

A press release from the Utah Department of Public Safety explained that the incident took place around 8:30 pm.

"A catering company lost their load of canvas bags on to the freeway. Two cars stopped, or nearly stopped for the debris. A green Ford F-250 came upon the stopped traffic and collided into a red Toyota Prius out of California. The Prius then struck a silver Chevy Malibu. Two occupants inside the Prius, an adult male and an adult female, sustained fatal injuries and died on the scene," it read. 

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"Another adult male was taken by medical helicopter in critical condition. The driver of F-250 had minor injuries was arrested for DUI. The occupants of the Malibu were transported by ground in serious condition."