Remember, Johnson, with influence over hundreds of millions of fans, threw his support behind Biden ahead of the 2020 election ... a big get at the time for the presidential hopeful.

Biden, who is struggling with approval ratings in the gutter (56% of Americans disapprove of POTUS' job performance) and poor polling numbers, could certainly use the help ... but it ain't coming. At least, not from the WWE legend.

"Am I happy with the state of America right now? Well, that answer is no," The Rock told FOX News' Will Cain, before adding he's hopeful the country can right itself.

"Do I believe we're gonna get better? I believe in that. I'm an optimistic guy, and I believe we can get better."

Then, 51-year-old Johnson brought up his endorsement of Biden and VP Kamala Harris ... which came just about four years ago.

"The endorsement that I made years ago with Biden was one I thought was the best decision for me at that time. And I thought back then when we talk about I'm in this position where I have some influence, and it's my job then, I felt like that then, it's my job now to exercise my influence and share. This is who I'm gonna endorse," DJ said about the rationale behind the decision.

"Am I gonna do that again this year? The answer is no," The Rock emphatically said ... revealing he would not be sitting down with Biden and Harris and throwing his support behind them, as he did last time.

Why not? Besides being unhappy with the current state of America, Johnson explained his decision didn't unify, but rather divided Americans.

"What I realized, and I didn't realize it back then," The Rock said, "what that caused back then was something that tears me up in my guts, back then, and now, which is division. And that got me."

DJ went on to explain he thought the endorsement could help calm the country ... but he now believes that was a mistake.

The Presidential election is 7 months away ... and most polls show Donald Trump ahead nationally by a handful of percentage points.