Kylie Jenner is rumored to be "freaking out" that her despised rival Blac Chyna might be plotting to pen a tell-all book about her.

According to Life & Style magazine, 18-year-old Jenner's fears were heightened by a recent conversation her rap star boyfriend Tyga had with Chyna, in which he reportedly lamented about the couple's mounting troubles. Tyga and Chyna were once a couple, and they have a young son together.

"Kylie thinks Blac's an opportunist and it upsets her that Tyga runs to his ex when they're having relationship problems, telling her everything that's going on in their relationship," a source said. "For all Kylie knows, Blac could be taking all the information and plotting to write a book, exposing what goes on behind closed doors with Kylie and Tyga."

Seemingly since day one of Jenner's relationship with the "Rack City" rapper, she and Chyna have engaged in an emotional battle, much of it playing out in mean-spirited tweets and posts left on social media.

The last several months have proven to be a trying time for the once enamored couple, with both of them dogged by allegations of infidelity.

Over the summer, a transgender woman known as Mia Isabella repeatedly claimed that she had engaged in a long-term affair with the rapper. Meanwhile, Miami-based rapper Stitches recently claimed he bedded and did drugs with Kylie soon after she celebrated her 18th birthday.

All the drama has seemingly caused the couple to hit the pause button on their once rapid plans to elope and move away from LA together.

Back then, the couple were reported to be considering New York City and Europe as possible destinations once they fled Los Angeles.