McGowan, the actor and whistleblower, made allegations on Twitter on Monday about an incident with Payne that occurred when she was 15. At the time, Payne would have been in his late 20s.
Based on McGowan's age, the incident would have occurred in the late '80s.
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"Alexander Payne," McGowan tweeted. "You sat me down & played a soft-core porn movie you directed for Showtime under a different name. I still remember your apartment in Silverlake. You are very well-endowed. You left me on a street corner afterwards. I was 15."
In another tweet, McGowan shared a photo of herself at 15 years old, writing, "I just want an acknowledgement and an apology. I do not want to destroy."
In a WhatsApp conversation with Variety, McGowan expanded on her tweet:
"I feel very badly for my 15 year-old self. I had auditioned for him. He took me home afterwards. I quit acting after that and then was discovered by Ilene Staple (a friend of Gregg Araki) 6 years later. It wasn't until after the HW [Harvey Weinstein] stories came out that I reframed the Payne of it all. I had for years looked at it as a sexual encounter, not understanding what it really was. It was a grooming situation. The first time I'd been shown a straight porn.'
"He left me on the corner in front of Café Tropical in Silverlake to find my own way home.
"I feel extreme emotional exhaustion today."
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Payne, the director of "Election," "Sideways" and "The Descendants," won two Oscars for best adapted screenplay: for "Sideways" in 2005 and "The Descendants" in 2012. Currently, Payne has a series in the works with HBO and Sky, "Landscapers," which is set to star Olivia Colman.
Monday's allegations are the first time McGowan has named Payne, but in the past, she has referred to an incident of alleged misconduct when she was 15.
In a conversation with investigative journalist Ronan Farrow in early 2018 at the 92nd Y, McGowan spoke about a sexual encounter with a "very famous" man when she was 15, and said she recently learned it was statutory rape and that she would eventually come forward with the man's name when she was ready. "He took me home, after he met me, and showed me a soft-porn movie he'd made for Showtime, under a different name, of course," McGowan said during the conversation with Farrow. "And then he had sex with me. And then he left me next to Tropical in Silver Lake, standing on a street corner."
When asked why she was ready to make the allegation against Payne now, McGowan said: "It just came over me. It was time."
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As one of the most prominent voices of the #MeToo movement, McGowan was one of the first women to come forward with allegations against Weinstein in October 2017, sharing that Weinstein raped her at the Sundance Film Festival in 1997 in his hotel suite. Weinstein is now serving a 23-year sentence in upstate New York, convicted on the charges of third-degree rape and first-degree sexual assault.