Kevin Hart -- Gettin' His Swole On ... With UT Football Team

Kevin Hart might be a man of the tiny variety but he proved his heart is as big as Texas Wednesday ... invading the UT locker room and working out with some of the biggest beasts in college football.

Hart is in Austin on a promotional tour for his movie "The Wedding Ringer" -- and decided to stop by the University of Texas workout facility for a sweat session with the Longhorns.

Of course, Hart took a bunch of photos with virtually anyone who wanted one -- but when it came time to grind, Kev hit the weights, ran a sled-drill and busted out some cardio.

UT is no stranger to celebrity visitors, having hosted Matthew McConaughey last season ... although the only muscle Matty worked out that day was his mouth (remember the inspirational speech?)

One last thing ... as far as we know, no quarterbacks were roasted during Hart's visit.