The 59-year-old Academy Award winner is alleged to have assaulted a teenager at a bar in Boston, Massachusetts, in July 2016.
According to the Cape and Islands District Attorney Michael O'Keefe, Spacey is due to be arraigned on a charge of indecent assault and battery at Nantucket District Court on January 7.
The alleged victim is the son of former US news anchor Heather Unruh, who first made the allegation during a press conference in November 2017.
Unruh said the actor bought her son "drink after drink" at a restaurant in Massachusetts before allegedly sticking his hand down the 18-year-old's pants and grabbing his genitals.
As reports of the charge emerged, a video was posted to Spacey's official Twitter account, his first social media post since he was initially engulfed in scandal in October last year.
In the clip, Spacey appears to be in the character of Frank Underwood from House Of Cards. The character was killed off by Netflix after the actor Anthony Rapp said he was 14 when Spacey, then 26, made a sexual advance to him in 1986.
The sixth and final season of the political drama started streaming on Netflix in November.
The video begins with Spacey in a kitchen, before he starts speaking directly to the camera.
He said: "I know what you want, and sure, they may have tried to separate us but what we have is too strong, is too powerful. I mean after all, we shared everything, you and I.
"I told you my deepest, darkest secrets. I showed you exactly what people are capable of. I shocked you with my honesty, but mostly I challenged you and made you think.
"And you trusted me, even though you knew you shouldn't. So we're not done, no matter what anyone says. And besides, I know what you want - you want me back.
"Of course, some believed everything and have just been waiting with bated breath to hear me confess it all, they're just dying to have me declare that everything said is true, and that I got what I deserved. Wouldn't that be easy, if it was all so simple."
Spacey added: "You wouldn't believe the worst without evidence would you? You wouldn't rush to judgments without facts would you? Did you? No, not you, you are smarter than that.
"I can promise you this; if I didn't pay the price for the things we both know I did do I'm certainly not going to pay the price for the things I didn't do."
He concluded: "Now that I think of it, you never actually saw me die, did you? Conclusions can be so deceiving. Missed me?"
It is not known whether Netflix is involved with the video and the streaming giant has been contacted for comment.
A lawyer for Spacey has also been approached.
Scotland Yard has six open sexual assault investigations into Spacey, alleged to have taken place in London and Gloucester.
Spacey, who was artistic director at London's The Old Vic theatre between 2004 and 2015, was one of the first Hollywood stars to face allegations in the wake of the Harvey Weinstein scandal.
His downfall started when Rapp made his allegations in 2017.
Spacey said he did not remember the encounter but apologised for any "inappropriate drunken behaviour".
He was sacked by Netflix's House Of Cards and Sir Ridley Scott erased him from his completed film All The Money In The World in re-shoots costing millions.