Joe Biden's proclivity to gaffe verbally has become legend. But on Wednesday, Biden found himself on the other end of a verbal slip when he was introduced as John McCain.

Jim Piccillo, a father of two -- and a former Republican -- who started campaigning for Obama after being laid off, stumbled at a rally at the University of South Florida.

"Please help me today in welcoming the next vice president of the United States ... John McCain!" Piccillo said to a cheering crowd of about 4,000.

Click here to see the video.

No one seemed to notice, and Biden didn't mention the gaffe in his speech. Piccillo said he didn't notice until more than an hour later when he and his girlfriend were driving home and listening to a country radio station. The DJ noted Piccillo's gaffe and played a recording of the introduction.

Piccillo has supported Barack Obama since the Democratic National Convention.