8:22 AM PT -- A rep for the Trump campaign tells TMZ ... "This is a completely fabricated and bull*** story that was already peddled in 2016."

They add, "Nobody took it seriously then, and they won’t now, because it’s fake news. Now that Crooked Joe Biden and the Democrats are losing the election, they are bringing up old fake stories from the past because they are desperate."

Rumblings about Donald Trump allegedly saying the n-word have circulated for years -- but now, an ex-producer on "The Apprentice" is definitively claiming ... yeah, he said it.

Bill Pruitt -- who was a producer on the first season of the hit NBC show in 2004, and who worked on the show for many years afterward -- just published an article on Slate that accuses the former President of uttering the word while discussing a Black contestant.

The guy claims DT said the n-word while mulling over the finalists for season 1 -- namely, Bill Rancic (who won the show that year in 2004) and Kwame Jackson, the runner-up.

Pruitt describes the moment this way ... he says him, Carolyn Kepcher (who ran Trump's hospitality units at the time), and Jay Bienstock (the 'Apprentice' showrunner at the time) were huddled up to discuss the last two guys ... who BP insists was a recorded moment.

He says this moment was meant to be filmed as a lead-up to Trump's ultimate decision -- and as the team briefed Trump on who they thought would be best ... he allegedly winced at the suggestion that Kwame should be considered as the top dog.

Pruitt says Kepcher told him ... "I think Kwame would be a great addition to the organization," to which Trump allegedly grimaced. Pruitt says Trump asked why Kwame didn't fire Omarosa after some problems ... and DT's team defended Kwame, saying he didn't have that power.

Then Trump allegedly said this ... "Yeah, but, I mean, would America buy a n***** winning?"

Pruitt says Kepcher went pale after hearing this ... and claims Trump continued to wince as he mulled it all over, seeming serious about not wanting Kwame to take first place. Bienstock then allegedly changed the subject and pivoted to George Ross, one of Trump's attorneys who was also supposedly in the mix for this conversation.

After that, Pruitt says no one acknowledged what Trump said ... and the alleged recorded moment never saw the light of day -- neither did other unsavory things he claims Trump said during filming. Trump has long denied ever saying it ... and there's never been proof.

However, this is the first time anyone's described the alleged utterance of it from Trump's lips.

We've reached out to Kwame, Bienstock and Kepcher ... so far, no word back. We've also reached out to Trump's camp about this ... no word back on that front either.