The anonymous victim also said that just before he ad Spacey had sex for the first time in 1983 the actor professed his love for the youngster.
"He is a pedophile," said the anonymous victim.
"Mr. Spacey absolutely denies the allegations," said the actor's lawyer.
Meanwhile, eight workers on the set of House of Cards tell CNN that Spacey sexually harssed them for years, and in one case assaulted a young man.
Spacey allegedly attempted to rape the teenager during what was to be a 15 minute visit claims the anonymous victim, who said he planned to stop in briefly before he had to meet his parents for dinner in the city.
"I guess he must have come up behind me and yanked down my baggy jeans, and he goes to f*** me and I'm like, 'No, I don't want to,'" said the victim.
"And he pushes hard, and grabs me, and starts shoving up against my a**hole, and it hurts like a motherf*****. I again tell him no, and he tries again."
The victim continued: "I am strong enough, thank God, both somewhere in my brain and in my body, to get him off of me. I'm sturdy, thankfully. I throw him off of me and I run crying down the stairs and out into the street and then suck it all up and go have dinner."
The victim was then asked how he would classify the incident.
"I always have said, 'He tried to rape me,'" he explained.
"I told him I didn't want that, he went again to do it, I told him no, he went again and pushed harder and grabbed me and pushed harder."
He then added: "I don't know how I would see that as anything besides an attempted rape, which I was able to thwart."
This came three years after the pair first met when Spacey was the boy's teacher at an upstate New York theater camp.
He was 12 at the time and said that nothing happened between the two, with their sexual relationship instead commencing after a chance encounter at Shakespeare in the Park.
The victim said he was with his parents, so he and Spacey went off on a walk together through the park.
"He was kind of in high seduction mode and gave me his phone number and asked me to call him," said the victim.
"He said, 'I want to see you, and I want you to come to my apartment.' He said he'd always been really drawn to me at the acting classes, but had stayed away because I was 12."
The teen was in Spacey's bed within 24 hours of that run-in he claims, adding that he was of the impression that the actor was in a relationship with Jenifer Jason Leigh.
"I called him on the phone the next day, and he told me how he was in love with me and wanted to see me," said the victim.
"I went and saw him at an apartment he was renting on the Upper West Side. He had a black Labrador named Snake. He might've been walking that dog in Central Park when we bumped into him that night."
He then stated: "We started a sexual relationship that first visit, which mostly involved me f***ing him."
That very illegal and very illicit relationship was further complicated by the fact that the teen was also sleeping with his cousin, who was the same age as Spacey.
That cousin had also sexually abused the victim's older brother.
At the time however, the victim thought that he was living an adult life, which is an appealing existence to most young teens.
He was also a working actor at the time.
"Of course I have a 24-year-old boyfriend and I'm going out to punk clubs. I'm lying to my parents about all of this," said the victim.
'And I'm 'cheating' on my cousin/boyfriend to go see Kevin Spacey. I'm very caught up in the drama."
It was around that time that the alleged near-assault took place, and the victim never again saw Spacey.
He had planned to see the actor briefly a year later when the two were both in Williamstown for the famed summer stock of shows, but at the last minute decided against the meeting.
It took him 10 years he said to truly understand the alleged relationship.
"I would call him a pedophile and a sexual predator," he said of Spacey.
'When I turned 25, I looked at every 14-year-old boy I could see, to try to understand what those men had seen, because I still on some level thought I had been a tiny adult.
"That whole year I was 25, I tried to just see the ones who were like six-foot-two, and 200 pounds - they all looked like children. They all looked like somebody who was 10 years old four years ago. Nobody looks f***able. Nobody."
That ultimately changed his perspective on who he believes Spacey is, and what was allegedly done to him when he was just a minor.
"Up until then, I just thought about him as somebody who had really done me wrong and tried to rape me, but not as somebody who had functioned as a predator," he said.
"And then, if you're interested in sexual predation, you start to read about it, and you realise all these patterns and techniques, and it all kind of falls within a set of practices."
Netflix announced earlier this week that they are cancelling Spacey's show 'House of Cards' after its sixth season, which is currently in production.
That news came after Spacey made the decision to come out of the closet in a statement apologizing to actor Anthony Rapp, who said in an interview that the actor attempted to sexually assault him in 1986, an incident Spacey says he does not remember.
Rapp was 14 at the time while Spacey was 26.
Media Rights Capital, who produces House of Cards, and Netflix released a joint statement on Monday saying they 'are deeply troubled by last night's news concerning Kevin Spacey,' who "as previously scheduled" is not currently working on set.
"In response to last night's revelations, executives from both of our companies arrived in Baltimore this afternoon to meet with our cast and crew to ensure that they continue to feel safe and supported,' said the two companies.
The show's creator Beau Willimon also weighed in, saying: "Anthony Rapp's story is deeply troubling. During the time I worked with Kevin Spacey on House of Cards, I neither witnessed nor was aware of any inappropriate behavior on set or off."
He went on to state: "That said, I take reports of such behavior seriously and this is no exception. I feel for Mr. Rapp and I support his courage."
There is also a chance that Spacey's character was never meant to be in the sixth season, with his character's health an issue throughout the five previous seasons of the show and the actor currently in the middle of shooting a Gore Vidal bio pic.
The incident that spurred this all allegedly took place at Spacey's apartment in 1986 when the actor invited Rapp to a party while they were both appearing on Broadway.
In an interview with Buzzfeed, Rapp said that he found himself alone in the apartment at the end of the night and that Spacey then began to make his move.
"He picked me up like a groom picks up the bride over the threshold. But I don't, like, squirm away initially, because I'm like, 'What's going on?' And then he lays down on top of me," said Rapp, who detailed being pressed up against the bed before being able to squirm away and ultimately leave the house without being assaulted by Spacey.
At the time, Spacey was just at the start of his illustrious professional career, having been selected by Jack Lemmon personally to star alongside him in the Broadway run of Eugene O'Neill's "Long Day's Journey Into Night."
That same year, he also scored his first big screen role with a cameo in the Nora Ephron comedy "Heartburn."
His brief part was that of a subway thief, whose failed attempt to steal the purse of the film's leading lady, played by Meryl Streep, is one of the more memorable parts of the movie.
He would go on to win the Oscar for Best Supporting Actor in 1996 for "The Usual Suspects" and the Best Actor trophy in 2000 for "American Beauty."
There was talk of Spacey possibly scoring another nomination this year as well for his work in the beloved summer hit 'Baby Driver' or the upcoming Getty biopic "All the Money In the World."
Spacey issued a statement soon after the Buzzfeed story was published on Sunday, which began with his claim that he did not recall this incident.
"But if I did behave then as he describes, I owe him the sincerest apology for what would have been deeply inappropriate drunken behavior," wrote Spacey.
"This story has encouraged me to address other things about my life. I know that there are other stories out there about me and that some have been fueled by the fact that I have been so protective of my privacy."
He then went on to state: "I now choose to live as a gay man."
This was a shocking statement from Spacey, who in 2010 said that being forced to reveal his sexuality was akin to being a bullied teen in an interview with The Daily Beast.
"I think what we have seen in terms of gay teenagers committing suicide because of bullying is anguishing. I think young people, if they are feeling like they are confused, need to know that there are people to talk to and that there are places they can go and not feel alone,' said Spacey.
"But I feel that they have just as many rights as I do to not be bullied. And I don't understand people who say, 'Well, this is a terrible thing that is happening to this young person whose life is being exposed,' and then turn around and do it to another person. People have different reasons for the way they live their lives. You cannot put everyone's reasons in the same box."
He then closed out his response by sating: "It's just a line I've never crossed and never will.'"
Rapp said after the publication of his story: "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."
