Henry Winkler tells TMZ Sports he and Patrick Mahomes do, indeed, have a genuine bromance going on ... and he said it's blossomed so much in the past few weeks -- they're actually going to do dinner soon!!!
The Fonz broke down the improbable friendship for us out at Il Pastaio recently ... explaining the whole thing actually started when he praised the Chiefs star during an interview on "The Rich Eisen Show" some six months ago.
Winkler called Mahomes one of his "heroes" ... and gushed over the QB's talent. A few months later, the 27-year-old signal-caller heard the kind words -- and invited him out to the Chiefs vs. Chargers game in LA.
Winkler ended up coming -- and the two shared an amazing moment in the pregame at SoFi Stadium. And, the 77-year-old acting legend tells us they've remained tight ever since.