Actor Taylor Kinney, second left, and his fiancée, pop star Lady Gaga, center, along with "Chicago Fire" cast take part in the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press
CHICAGO (AP) - Lady Gaga and Vince Vaughn plunged into the icy waters of Chicago's Lake Michigan at a fundraiser for the Special Olympics.
Special Olympics Chicago President Casey Hogan said Sunday that Lady Gaga made the plunge with more than 4,500 other participants. Hogan says the singer's appearance was "a very nice surprise."
Lady Gaga recently announced her engagement to "Chicago Fire" actor Taylor Kinney. Photos show her and a bare-chested Kinney going into the water together.
Vaughn also made the plunge. The native of the Chicago suburb Lake Forest was dressed in a Chicago Blackhawks jersey and jeans. The actor went in up to his knees, then eased himself down backward in the water.
Last year, comedian Jimmy Fallon jumped in wearing a suit and tie, and helped raise more than $1 million.
The air temperature was a frigid 20 degrees at the time of the plunge, according to the National Weather Service.
Actor Taylor Kinney, left, kisses his fiancée, pop star Lady Gaga, before the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press
Pop star Lady Gaga, top, gets a piggy back ride from her fiancée, Taylor Kinney, as they and members of the "Chicago Fire" cast take part in the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press
Pop star Lady Gaga, top center, gets a piggy back ride from her fiancée, actor Taylor Kinney, as they and members of the "Chicago Fire" cast take part in the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press
Actor Taylor Kinney, left, and his fiancée, pop star Lady Gaga, along with members of the "Chicago Fire" cast, take part in the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press
Actor Taylor Kinney, center left, holds his fiancée, pop star Lady Gaga, as they and members of the "Chicago Fire" cast take part in the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press
Actor Vince Vaughn takes part in the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press
From second left, Chicago Park District CEO Mike Kelly, actor Vince Vaughn and Special Olympics Chicago President Casey Hogan take part in the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press
Actor Vince Vaughn, center, waves before taking part in the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press
Actor Vince Vaughn, center left, and Special Olympics Chicago President Casey Hogan take part in the Chicago Polar Plunge at North Avenue Beach on Sunday, March 1, 2015 in Chicago. (Photo by Barry Brecheisen/Invision/AP)
The Associated Press