This memo is out of this world.

Mysterious sightings of ‘three to four-foot tall’ beings decked out in space suits and helmets were reported by witnesses decades ago, newly released Pentagon files reveal.

The astonishing accounts were included in an internal FBI memo dated Oct. 19, 1966 with the subject line “Unidentified Flying Objects” — released to the public on Friday — that claims that “1965 was the year of the greatest number of UFO sightings.”

The most shocking revelation in the memo came from a witnesses that “reported seeing crewmen who had landed from” apparent UFOs, “who are described as three and a half to four feet tall, wearing what appear to be space suits and helmets.”

The memo primarily focuses on the book “Flying Saucers – Serious Business” by Frank Edwards, which was described as a potential contributor to the growing fascination and controversy surrounding UFOs by the public at the time.

The memo details Edwards’ eerie claims that UFOs were “space vehicles sent to observe activities on earth” and stated the United States Air Force had “deliberately withheld information and given misleading explanations because it fears a mass panic by the public if the public were told the truth.”

The author describes “UFOs as polished metal objects, radiating heat and light (sufficient to have burned witnesses who were too near),” according to the memo.

The UFOs “range from brilliant white to dull reds and brilliant orange” with some having “blind striking lights,” Edwards claimed in his book.

Edwards also claims there are three “basic shapes” of UFOs; zeppelin-shaped ships that span up to 300 feet long, disc shaped objects with a diameter range of a few feet to 100 feet, and egg shaped objects — which were the most recently sighted UFOs, the memo says.

The UFOs sighted could move silently at “fantastic speeds” while also suspending motionless mid-air before speeding away with strobes of light from underneath the object, according to the document.

The FBI claims in the memo that many people who reported sightings and are named in the book are “reliable individuals” ranging from law enforcement officers, military personnel on official duty and commercial airline pilots.

Wreckage from crashed objects has been recovered on at least three occasions — including magnesium alloy, pure magnesium and an “exceptionally hard unknown metal” that contained “15-micron metal spheres” with evidence of “micro-meteorite impacts on its surface,” according to the file.

The memo concluded by mentioning Edwards’ prediction that UFOs would soon make an “overt landing” or deliberately make contact with Earth.

While a trove of 162 UFO files were released Friday — made up of photographs and video footage as well as numerous witness accounts including a 1947 sighting of a “flying disc” — the Trump administration insists that additional documents will be released on a rolling basis in the coming weeks.