Ben Affleck Slurring, Ranting ... On HBO Talk Show

(WARNING: EXPLICIT LANGUAGE)

Ben Affleck appeared on the series premiere of Bill Simmons' "Any Given Wednesday" and it was extremely bizarre ... to say the least.

A red-faced Affleck ranted about "Deflategate" on the HBO show and even though we can't say for sure what was up with him ... social media was quick to call Affleck out for his slurred speech and angry tone.

Sources close to Affleck tell us he's stone-cold sober, and the slurring is just how passionate he is about Tom Brady. We're told he and Simmons got into a heated, loud debate before cameras started rolling. So when the taping started at 11 AM, Ben was already fired up.