Kevin Spacey, who is 59, was charged in January with indecent assault and battery. (File)

A young man who accused Kevin Spacey of a sexual assault in a Massachusetts bar has dropped his lawsuit against the award-winning actor.

A motion for "voluntary dismissal" of the civil complaint against the former "House of Cards" star was filed in Superior Court in Nantucket, Massachusetts, with no reason given.

Possible motives for the dismissal this week include a private settlement or the accuser's desire not to risk damaging his odds in a separate criminal case with the civil suit, which was filed just six days ago.

William Little's lawyer, Mitchell Garabedian, who made a name for himself defending victims of sexual abuse by Catholic priests, gave no comment.

A hearing on the criminal charges against Spacey is set for Monday in the District Court in Nantucket, the posh island community where the alleged aggression took place in July 2016.

Little has said he took a smartphone video of the incident, which he says took place when he was an 18-year-old busboy in a Nantucket bar/restaurant.

The smartphone images, which Little has said he shared with a then-girlfriend, allegedly show Spacey shoving his hand into the teen's pants and fondling him.

But the plaintiff's lawyers say they have been unable to find the smartphone, which Spacey's defense team has demanded to see.

Little has said he has not seen the phone since handing it over to police investigators in December 2017. Police say they turned it over to the young man's father, but he says he has "no memory" of it.

If the phone is not located by Monday, the District Court judge has said he will call on Little to testify about it.

Spacey, who is 59, was charged in January with indecent assault and battery.

The actor has insisted on his innocence. The charges carry a penalty of up to five years in prison.

The allegation of sexual misconduct against the two-time Oscar winner was one of more than a dozen to emerge since 2017 -- in both the United States and Britain -- with devastating effect on his acting career.

He was dropped from the cast of the popular "House of Cards" series and from a leading role in director Ridley Scott's "All the Money in the World"; Christopher Plummer was brought in as a last-second replacement.