12:48 PM PT — The Craigslist post has been officially debunked as fake — Fight Fight Fight LLC telling TMZ … they know nothing about it.

An ad posted to Craigslist calling for seat-fillers for the U.S. Army’s 250th anniversary parade this weekend — AKA President Trump‘s birthday bash — has gone viral … but it has all the makings of a total hoax.

Here’s the deal … an ad posted this week on the D.C. website page with the headline “Seat Fillers Needed – June 14th – Constitution Avenue – DC” claims patriotically dressed seat-fillers would be paid a freaking grand — in crypto — to show up and cheer their butts off Saturday.

But .. there are some red (sans white and blue) flags with the post … for instance, the alleged coordinator — T-Mellon Events — doesn’t appear to exist, so far as TMZ could find while searching for business records. What’s more — on ALL of Craigslist in the U.S., T-Mellon Events only appears on this single listing.

The White House tells TMZ … the posting is bogus — specifically, in their favorite term: “Fake news.”