Joe Namath -- Fur Coat Was Last-Minute Purchase

Joe Namath's show-stopping fur coat was a last-minute purchase that he decided he "HAD" to have after seeing it at a fur store just days before the Super Bowl ... TMZ Sports has learned.

Turns out, Namath picked up the coat on Wednesday from Marc Kaufman Furs in NYC.

We spoke with Kaufman himself, who told us Joe came into the store with his daughter and was on a mission to find the perfect fancy coat for the Super Bowl coin flip.

That's when Joe noticed a white stunner on one of the racks -- which was comprised of a coyote-base mixed with some white fox.

We're told Joe said, "This is perfect for me" ... and decided he had to have it.

Kaufman says the coat ran Joe a cool $3,000.

And get this ... Kaufman says Namath's fashion statement has been huge for business -- "My phone hasn't stopped ringing."