"The Tonight Show" host says he didn't know about the Polar Plunge when he agreed to take part with Chicago Mayor Rahm Emanuel.
Jimmy Fallon's wet feet are going to turn into cold feet on Sunday.
"The Tonight Show" host told his audience on Wednesday that he accepted Chicago Mayor Rahm Emanuel's challenge to take part in the Polar Plunge without really knowing what he was getting into.
"Of course I said, 'Yeah, I'm in. Yeah, I'm in. Polar Plunge. That's me! Let's do it!'" Fallon said with bravado before pausing -- "I have no idea what the Polar Plunge is."
Of course, he quickly learned the annual event involves a jump into Lake Michigan. In Chicago. In March.
"It sounds like a nightmare," quipped Fallon. "You run into Lake Michigan and I'm going to jump in with the mayor, and it's freezing in Chicago right now."
#SwimmyFallon, as he came to be known on Twitter, agreed to take part in the plunge to benefit the Special Olympics after a nearly week-long exchange with Emanuel.
It all started when Fallon openly expressed his desire to have Emanuel on the show. The mayor agreed to do it if Fallon took part in the Polar Plunge. The twitterverse got involved, egging Fallon on with the hashtag #JimmyPlungeWithUs, and the comedian on Wednesday finally confirmed he'd take part.
"I'm a man of my words. I'm a man of my tweets," said Fallon.
NBC Chicago is a media sponsor for Sunday's event at North Avenue Beach. Forecast models predict temperatures in the 20s with steady snow that could become heavy that morning.