"The Tonight Show" host made good on his promise to make Sunday morning's "Polar Plunge" with Mayor Rahm Emanuel as a condition for the mayor appearing on Fallon's show in New York, following an exchange of tweets and challenges.
"If you hear a scream like a little girl's ... know that Jimmy Fallon is swimming in Lake Michigan,Sac ?? Dos Kanken 16l," Fallon told the crowd shortly before running in.