Mel Gibson JACKED — Check Out My Lethal Weapons

Exclusive 0819_mel_gibson_muscles_launchMel Gibson is only hitting one thing these days … the gym … just check out the diesel arms he unveiled in L.A. on Friday.

Makes sense. 57-year-old Gibson is set to play the villain in next year”s action flick “Expendables 3” alongside equally yoked middle-aged actors Sylvester Stallone, Arnold Schwarzenegger, Jason Statham, and Dolph Lundgren … so bulking up is kind of expected.

But we”re still blown away, and not just by Gibson”s guns. We don”t think we”ve ever seen the guy in a tank top before.