Discovered in May 2014 and subsequently named 2014 JO25, the asteroid passes just 0.01175 astronomical units (1.09 million miles, or 4.57 lunar distances) from Earth at 12:24 UT (1:24pm BST) on Wednesday, 19 April.
What size are we talking about?
According to a report from NDTV, "The Rock" is as big as the Rock of Gibraltar, with roughly 650 meters, or 2,000 feet across. That's about 670 yards (613 meters), or about the length of six NFL football fields.
Asteroid 2014-JO25 is a kilometre across and will come closer to the Earth than any asteroid of its size in 13 years. The object that poses the greatest impact threat to Earth is asteroid 29075, which is 1.3 kilometres long.
2014-JO25 won't be the only visitor in our part of the Solar System on April 19th, as the PanSTARRS non-periodic comet will also by flying by that day at a distance of 175 million km. One can see it for the next consecutive days with the help of small optical telescopes.More news: Cahill urges Chelsea to dig in after United defeat
The upcoming encounter with Earth is also the closest by any known asteroid of its size or larger and the next known encounter of something this size won't occur until 2027, NASA scientists said in a news release.
If you don't have your own telescope, you can watch the asteroid online.
Scientists have been waiting for this near-Earth asteroid, known as 2014 JO25, since it first appeared as a fuzzy ball in the Catalina Sky Survey in May 2014. It will be at its closest point to Earth at 8:24 a.m. EDT (1224 GMT). NASA said telescopes around the world will be trained on it during the flyby to try to learn more about it.
NASA said it is an outstanding opportunity for astronomers and amateur stargazers.
In case you miss it, the next time it comes around again will be in another 500 years! While there isn't any chance it will hit Earth, it is a startling reminder of how close space debris comes to smacking into the planet all the time.