Mila Kunis

Actress Mila Kunis has claimed a film producer threatened to end her career after she refused to pose half-naked for a men's magazine.

The Hollywood star said the unnamed producer told her "You'll never work in this town again" when she declined to take part in the provocative photo shoot for a movie being promoted.

In an open letter published on A Plus, a website co-founded by her husband Ashton Kutcher, Kunis said she was "livid" and felt "objectified" following the incident and voiced concerns about gender inequality in the workplace.

She wrote: "Throughout my career, there have been moments when I have been insulted, sidelined, paid less, creatively ignored, and otherwise diminished based on my gender.

I taught myself that to succeed as a woman in this industry I had to play by the rules of the boys' club

"I taught myself that to succeed as a woman in this industry I had to play by the rules of the boys' club. But the older I got and the longer I worked in this industry, the more I realised that it's bullshit! And, worse, that I was complicit in allowing it to happen."

Kunis, 33, referred to another incident after she formed a production company with three women, in which an "influential male producer" described her as "soon to be Ashton's wife and baby momma" during a discussion about a possible work project.

The Black Swan star wrote: "He reduced my value to nothing more than my relationship to a successful man and my ability to bear children.

"It ignored my (and my team's) significant creative and logistical contributions. We withdrew our involvement in the project."

Kunis said she vowed to stand up to sexist comments, adding: "I'm done compromising; even more so, I'm done with being compromised.

"So from this point forward, when I am confronted with one of these comments, subtle or overt, I will address them head on; I will stop in the moment and do my best to educate.

"If this is happening to me, it is happening more aggressively to women everywhere."

Kunis and Kutcher, who married in July last year, are expecting their second child after the birth of their daughter Wyatt Isabelle in October 2014.