Former Prez BILL CLINTON not only thinks extraterrestrials are real but confesses to a secret investigation of  AREA 51 and the infamous Roswell UFO crash.

Big Bill was a guest on last night’s ep of “Jimmy Kimmel Live” where he that shortly after becoming Commander in Chief, he had his aides immediately perform a thorough investigation of  Area 51, the Nevada military facility, “to make sure there was no alien down there.”

Bill also probed the reality of the infamous Roswell, New Mexico reputed UFO crash in 1947 which celebrated its 50th anniversary as the legendary incident celebrated its 50th anniversary during Clinton’s presidency.

“I had all the Roswell papers reviewed – everything,” Bill told an all-ears Kimmel.

“If you saw that there were aliens there, would you tell us?”

“Yeah,” Clinton said, nodding in assent.

Clinton believes we’re not alone, given the vast immensity of the universe and the billions upon billions of potentially habitable planets out there.

“If we were visited someday I wouldn’t be surprised,” Clinton said. “I just hope it’s not like ‘Independence Day.’”

But, Bill, possibly a secret sci-fi fan, thought there might be an actual benefit to an HG Wells-style invasion from outer space.

“It may be the only way to unite this increasingly divided world of ours … think about all the differences among people of Earth would seem small if we feel threatened by a space invader,” Clinton said.

“That’s the whole theory of ‘Independence Day. Everybody gets together and makes nice.”

After the world is nearly destroyed, natch.