Mila Kunis says that a film producer threatened to end her career after she refused to pose semi-naked.
The star said the man told her she'd "never work" in Hollywood again if she didn't take part in the magazine shoot.
In an open letter published on A Plus, Mila Kunis said she felt "objectified".
"Throughout my career, there have been moments when I have been insulted, sidelined, paid less, creatively ignored, and otherwise diminished based on my gender," she writes.
"I taught myself that to succeed as a woman in this industry I had to play by the rules of the boys' club.