Charlie Sheen has "categorically denied" explosive allegations he sexually assaulted Corey Haim when the late actor was 13.
Haim's friend, actor Dominick Brascia, made the claims to the National Enquirer, alleging the assault occurred during the filming of the 1986 movie, Lucas.
"Charlie Sheen categorically denies these allegations," a representative for the actor told The Hollywood Reporter.
Brascia told the National Enquirer that Haim had told him Sheen, then 19, "had sex with" Haim, then 13, when they co-starred in the film.
"He told me they smoked pot and had sex," Brascia said.
"Haim said after it happened Sheen became very cold and rejected him. When Corey wanted to fool around again, Charlie was not interested."
The Enquirer's report claimed four sources backed Brascia's testimony.
"Corey was so confused by the sexual encounter he believed, like so many victims, he was 'in love' with his abuser," an unnamed source added.
Haim, who became an '80s teen heartthrob with roles in films including The Lost Boys, License to Drive and Dream a Little Dream, died of pneumonia in 2010, aged 38, following years of drug addiction.
The Enquirer's report noted that Haim's close friend and frequent co-star actor Corey Feldman hinted at the incident in his 2013 memoir Coreyography.
"At some point during the filming [of Lucas], Haim explained an adult male convinced him it was perfectly normal for older men and younger boys in the business to have sexual relations, that it was 'what all guys do'," Feldman wrote.
"So they walked off to a secluded area between two trailers during a lunch break for the cast and crew and Haim, innocent and ambitious as he was, allowed himself to be sodomised."
The Enquirer's report, described as a "five-year probe" into Haim's death, also features testimonies from "eight witnesses from the Lucas set" who allege Sheen preyed on young female extras during shooting of the film.
The allegations come in the wake of renewed focus on Hollywood's culture of sexual misconduct, following exposes on movie mogul Harvey Weinstein and actor Kevin Spacey.
Last month, Feldman announced he would "name names" of Hollywood men he says were involved in child sex abuse.
He has since accused two men, including actor John Grissom, of molesting him as a child. On Wednesday, the LAPD confirmed they were investigating his claims.