Tony Gonzalez: I Showed My Butt Like Gronk ... For A Good Cause

EVERYONE'S GOT THEIR CAUSE

Gronk isn't the only future Hall of Fame tight end to bare his buns to the world ... 'cause NFL legend Tony Gonzalez says he publicly stripped down too ... but for a good cause.

Gonzalez was out at Bristol Farms when we asked for his thoughts on Gronk's nude shoot in GQ ... and if he'd ever strip down and show off the goods himself.

Check out the clip -- Tony lets us know he beat Gronk to the punch ... saying him and the lovely wife took it all off for PETA way before Gronk actually showed Hailey Clauson his scoring machine.

Take a look below ... Tony in all his glory.