The "Jackass" star was detained by authorities and reportedly cited Thursday for trying to bring a "prohibited item" on a flight after an airport screener spotted the grenade in the actor and TV personality's carry-on bag.
"I was filming some commercials for this show we are doing for MTV called 'Nitro Circus,' so I took a bunch of silly props in my carry-on bag to the shoot," Knoxville said in a posting on his Web site Jackassworld.com later Thursday. "Well, when the shoot was over, the wardrobe girl packed my luggage, so I could go home and, unbeknownst to me, she packed a fake hand grenade -- a prop grenade that I'd taken to the shoot -- in the front zipper of my luggage. Needless to say, when I was packing to go out of town this morning with my girlfriend and daughter, I didn't see the fake grenade in my luggage."
Knoxville admitted he was "bummed" when he realized what had happened.
"The cops did their job and verified that it wasn't real," Knoxville added. "Also, they were cool as they could be to me, considering the situation, and it is no one's fault, but my own. I should have checked my (expletive) luggage through and through, but I didn't and now we have this incident."
He emphasized that reports claiming he was carrying a real grenade are untrue.
"If it was real, I never would have been allowed to board my flight to Miami an hour later," he said.