The alleged assault happened at the Club Car Restaurant after Unruh said Spacey bought her son "drink after drink" until his was intoxicated.
The press conference was announced in a press release from the office of lawyer Mitchell Garabedian, who has represented sexual abuse victims of Catholic priests.
Former Channel 5 anchor Heather Unruh is expected to speak at a news conference in Boston Wednesday to accuse actor Kevin Spacey of sexual abusing her family member.
Famed author and journalist Gay Talese has a message for all the alleged victims of actor Kevin Spacey's sexual misconduct: "Suck it up".
News had come that afternoon that Netflix was cutting ties with the House of Cards star after multiple men had accused him of sexual harassment, beginning with actor Anthony Rapp, who told BuzzFeed that Spacey made a sexual advance towards him in 1986, when he was 14. She told him to run, and he did.
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Unruh said her son told Spacey that he was of the legal drinking age. "As he says, it's always there and it continues to bother him", she said. "And shame on you for using your apology to Anthony Rapp to come out as a gay man", Unruh angrily said. "Last week my son filed a police report and handed over evidence to the Nantucket Police and now a criminal investigation has begun", she said. Unruh said she made a decision to speak out after the Harvey Weinstein scandal came to light, with multiple allegations of sexual misconduct, harassment and assault surfacing in bombshell reports by The New York Times and The New Yorker. Spacey apologized in an October 29 tweet - his last - but also said he had no memory of the alleged encounter. Police are now conducting an investigation, she said. London police are reportedly investigating Spacey for a 2008 sexual assault.
"The #weinsteinscandal has emboldened me- #truth time", she tweeted.
"To Kevin Spacey, I want to say this: Shame on you for what you did to my son", Unruh said as she fought back tears. Time the dominoes fell'.
As the allegations against Spacey continued to surface, Unruh has shown her support for Rapp and the other victims on Twitter.
Representatives for Spacey did not immediately respond to a request for comment. A publicist said last week that Spacey is "taking the time necessary to seek evaluation and treatment".