In the unprecedented rant, McGowan accused Winfrey of being fake, being friends with exiled movie producer Harvey Weinstein and somehow "destroying" disgraced music producer Russell Simmons' alleged victims.
"I am glad more are seeing the ugly truth of @Oprah," Rose posted and pinned to her page on Aug. 29, tagging the best-selling author and former talk show host. "I wish she were real, but she isn't."
"From being pals with Weinstein to abandoning & destroying Russell Simmon's [sic] victims, she is about supporting a sick power structure for personal gain," she continued. "She is as fake as they come."
McGowan went on to add, "#lizard," which – according to the internet – is "a metaphor for bad leadership and a culture of followership that doesn't feel capable of calling out."
Weinstein – whose lengthy list of alleged sexual assaults dates back to the 1970s – was the catalyst for the far-reaching #MeToo movement, which began in October of 2017 and has since helped hold abusers of power across all industries accountable for sexual harassment and misconduct.
McGowan was one of the first of dozens of alleged victims to publicly come forward with claims against Weinstein, who was found guilty of two felonies last February and will likely spend the rest of his life behind bars.
Aside from the seemingly years-old image of Harvey and Oprah, it is unclear what kind of relationship – if any – they had or have.
Meanwhile, Simmons' reputation is almost identical to that of Weinstein; the ex-husband of Baby Phat designer Kimora Lee Simmons has been accused of rape and sexual misconduct by 20 different women.
Winfrey's ties to Simmons are a little more clear, though they still don't seem to merit the messaging put out by McGowan.
Last year, Oprah was set to executive produce a documentary about Russell's alleged sexual misconduct; however, she ended up backing out of the project because she said she and the film's directors could not agree upon how to tell the women's stories.
"I want it to be known that I unequivocally believe and support the women," she added at the time. "Their stories deserve to be told and heard. In my opinion, there is more work to be done on the film to illuminate the full scope of what the victims endured, and it has become clear that the filmmakers and I are not aligned in that creative vision."