Rebel Wilson says Sacha Baron Cohen is trying to stop her from ...

Australian actor Rebel Wilson said British actor and comedian Sacha Baron Cohen is trying to stop her from writing about him in a chapter of her memoir.

Wilson posted a story to her Instagram Sunday identifying her "The Brothers Grimsby" co-star as "the a--hole" she will be writing about in her upcoming book, "Rebel Rising."

"I will not be bullied or silenced by high priced lawyers or PR crisis managers. The ‘a--hole’ that I am talking about in ONE CHAPTER of my book is: Sacha Baron Cohen," Wilson wrote of the "Borat" star.

The "Pitch Perfect" actor previously posted to her Instagram a video in which she spoke about older colleagues in Hollywood, saying they had a "no a--hole policy."

"But then it really sunk in what they were meaning by that — older people in the industry — because I worked with a massive a--hole, and yeah, now I definitely have a ‘no a--holes policy,'" she said in the video. "The chapter on said a--hole is chapter 23. That guy was a massive a--hole."

A representative for Cohen said Wilson's claims are "demonstrably false."

"While we appreciate the importance of speaking out, these demonstrably false claims are directly contradicted by extensive detailed evidence, including contemporaneous documents, film footage, and eyewitness accounts from those present before, during and after the production of 'The Brothers Grimsby,'" the representative told NBC News.

Wilson and Cohen starred in 2016's "The Brothers Grimsby" together, where they played a couple who shared nine children.

Wilson's memoir is due to drop on April 2.