The lawsuit filed Wednesday says the prominent director of the forthcoming "X-Men: Days of Future Past" forced Michael Egan III into sex during parties in California and Hawaii when he was 17 in the late 1990s.
Singer's attorney, Marty Singer, said in a statement that the claims are absurd and defamatory.
"It is obvious that this case was filed in an attempt to get publicity at the time when Bryan's new movie is about to open in a few weeks," said Marty Singer, who said he is not related to the director.
"X-Men: Days of Future Past" is set for release May 23. It has an all-star cast, including Jennifer Lawrence, Hugh Jackman, Michael Fassbender, Halle Berry and Patrick Stewart. It's the fifth film in the blockbuster franchise.
Egan and his attorney, Jeff Herman, planned a news conference Thursday in Los Angeles.
The lawsuit claims Egan was lured into a sex ring with promises of auditions for acting, modeling and commercial jobs. He was paid as an actor for a digital entertainment company, but forced to have sex with adult men at parties notorious within Hollywood's entertainment industry, the lawsuit said.
The lawsuit says that Bryan Singer attended several of the parties and forced Egan into sex, giving him drugs and threatening Egan when he resisted advances. It does not accuse the director of luring Egan into the ring.
"Hollywood has a problem with the sexual exploitation of children," Herman said in a statement Wednesday night.
The lawsuit does not specify a total dollar amount, but says Egan is seeking more than $75,000 on each of four accusations: intentional infliction of emotional distress, battery, assault and invasion of privacy.
The Associated Press does not typically name victims of sex abuse, but is naming Egan because the lawsuit was filed civilly, Egan's lawyer Herman identified him and said Egan planned to speak publicly.
The lawsuit is possible in Hawaii because of a state law that temporarily suspends the statute of limitations in sex abuse cases.
Bryan Singer, 48, has had a lengthy career behind the camera, directing several movies including "The Usual Suspects," ''Superman Returns" and "Jack the Giant Slayer."
Herman has made a career of representing victims of sex abuse, filing lawsuits against organizations such as the Roman Catholic Church and Boy Scouts of America. In 2011, Herman won a $100 million verdict against a Catholic priest who was accused of molesting dozens of boys.
Marty Singer represents many of Hollywood's elite, recently winning a case for actor Ryan O'Neal in which the Oscar-nominee was accused of improperly taking an Andy Warhol portrait of his longtime partner Farrah Fawcett without permission after her death. He also represented John Travolta in a series of lawsuits filed by masseurs who accused the actor of inappropriate conduct during massages.