Running alongside those who signed up could be over 519,000 more who have responded as "interested". Meanwhile, nearly 650,000 people expressed interest in participating as of the time of the publication of this article.
"If we Naruto run, we can move faster than their bullets", the posted event said of their planned September invasion, referencing a popular Japanese manga and anime ninja protagonist.
"Let's see them aliens", the event hosts wrote in an apparent effort to rally the troops.
The CIA only officially acknowledged Area 51's existence in 2013, and its primary goal remains classified, though it has been the site of hundreds of nuclear weapons tests and stealth aircraft flights.
Area 51 on Google Maps.
According to ComicBook.com, a news site covering comics, TV shows and movies, a social media user who goes by the name "SmyleeKun" and who devised the Facebook page is "best known for posting memes and streaming to fans on Twitch", a live streaming platform used by gamers. But it's also caught the attention of the Defense Department.
However, the US Air Force apparently took the potential threat to Nevada base seriously, with spokeswoman Laura McAndrews saying she would like to "discourage anyone from trying to come into the area where we train American armed forces".
The U.S. Air Force facility commonly known as Area 51 is shown in a satellite image, alongside an alien sculpture in Baker, California, also known as the "Gateway to Area 51".
The event, which Joe Rogan said he partially feels responsible for after recently having Area 51 whistleblower Bob Lazar on his podcast, was created as a joke but nobody expected it to generate such enormous attention. However, it has only been described as an aviation test site.
A warning sign marking the boundary of Area 51, in Rachel, Nevada on March 12, 2000.
In 1955, the mysterious area was chosen by the Central Intelligence Agency as a testing site for the super-secret Lockheed U-2, a high-altitude reconnaissance aircraft.
It all may be a joke or a lark for numerous supposed UFO seekers.