updated 03/02/2014 AT 12:00 PM ET
•originally published 03/02/2014 AT 12:30 PM ET
Live, from Lake Michigan, it’s Swimmy Fallon!
It was a frigid Oscar morning for Tonight Show host Jimmy Fallon who answered a challenge from Chicago Mayor Rahm Emanuel to take a dip in Lake Michigan to benefit the city’s Special Olympics.
Fallon, 39, had asked Emanuel to join him as a guest on his new NBC show, but the steely mayor, a former White House chief of staff and friend of President Barack Obama, threw down the gauntlet and agreed – only if the comedian would participate in the annual “Polar Plunge,” the Chicago Tribune reported.
With temps at 10 degrees Sunday and water temperatures at about 32 degrees, it was a test of courage for both men, but a challenge Fallon couldn’t pass up when Emanuel taunted him to “toughen up.”
Fallon RSVP’d Monday for the event on Twitter: “Okay @Rahm Emanuel. I’m in. Lake Michigan will have a New York fish this weekend #SwimmyFallon.”
Fallon later said he’d take his icy dip wearing a suit and tie, and encouraged his fans to “show solidarity by wearing a necktie. (I’m not telling you what else to wear.)”
The mayor, known for his spicy repartee, said no to the business attire.
Emanuel agreed to his own plunge after Chicago students answered his challenge to read 2 million books over the summer.
Fallon made his way Sunday morning through the snow, posting Instagram pics. He later bragged of his icy accomplishment: “Officially PLUNGED!!!!! Thank you Chicago!!! Thank you Mayor. #polarplunge #coldneverbotheredmeanyway #frozen.”