The actor -- who says he's never spoken to Spacey about the incident, though he did recount the same story with names redacted in a Q&A with The Advocatein 2001 -- said he is coming forward now in the wake of the allegations against Hollywood producer Harvery Weinstein.
"Part of what allowed the Harvey situation to occur was that there was this witting and unwitting conspiracy of silence,” he said. “The only way these things can continue is if there's no attention being paid to it, if it's getting forgotten.”
Rapp said that he's had several encounters with Spacey in professional settings in the years since the alleged incident, recalling, “I certainly didn't want to make eye contact with him...It felt like I was trying to disappear.”
“My stomach churns,” he explained. “I still to this day can't wrap my head around so many aspects of it. It's just deeply confusing to me.”
Following the Buzzfeed report, Rapp told ET in a statement, "I came forward with my story, standing on the shoulders of the many courageous women and men who have been speaking out, to shine a light and hopefully make a difference, as they have done for me. Everything I wanted to say about my experience is in that article, and I have no further comment about it at this time."
ET has reached out to Spacey representatives for comment.
For more on the Weinstein scandal, watch the video below