Haim Eshed reportedly told the Israeli publication Yediot Aharonot he can confirm the existence of aliens, because he claims they've been among us for a damn long time. He even says they have their own org ... the "Galactic Federation."

Not only that, but Eshed -- who worked for the Israeli government from '81 to 2010 -- also alleges President Trump was about to blow the lid off the whole thing recently, but that he was convinced to shut his trap, 'cause most humans weren't ready for the truth ... yet.

The 87-year-old reportedly said, "There’s an agreement between the U.S. government and the aliens. They signed a contract with us to do experiments here. They, too, are researching and trying to understand the whole fabric of the universe, and they want us as helpers."

So ... they come in peace???

One more outlandish claim -- Eshed said there's an underground space base on Mars RIGHT NOW, where man and alien are working side-by-side for the betterment of the "Federation."

Ooookay ... so why's he going public? Much like comedy, Eshed says it's all about timing -- noting that if he had brought this up 5 years ago, he would've been written off as nuts.

BTW, plenty of people are still going with that take ... insinuating the dude's not all there anymore.

Conspiracy theorists, on the other hand, are pointing to Trump's fascination with ramping up Space Force, as evidence Eshed's on to something. And, don't get us started with UFO sightings either.

Remember, Obama all but confirmed the existence of aliens himself too -- but wasn't as loose-lipped as old Haim is here.