Katy Perry Set for Free Obama Concert in Milwaukee

Katy Perry will perform her third concert for Barack Obama's reelection campaign at a grassroots rally with the president on Saturday in Milwaukee, Wisconsin.

Perry has become Obama's most popular entertainer with young voters this election season. More than 13,000 people lined up to hear the singer at an Obama rally on Oct. 24 in Las Vegas, where Perry wore a white latex dress printed with an image of a giant ballot.

At a fundraiser concert in Los Angeles, Perry's fans took to Twitter with photos of the pop star singing in a Statue of Liberty outfit and a stars and stripes cape. She tweeted: "I sang for President @BarackObama last night because I believe in Equal Rights #ForAll #Vote."

PHOTOS: 20 Biggest Political Players in Hollywood

With the campaign in its final days, Obama is calling on his celebrity supporters to help get out the vote. Eva Longoria is scheduled to appear alongside the president in Las Vegas today, while the first lady is campaigning in Florida at events featuring Stevie Wonder and Marc Anthony. On Saturday evening, Obama will join former President Bill Clinton and singer Dave Matthews for at a grassroots event in Bristow, Virginia.

The Las Vegas Sun noted on Thursday that in the past two weeks Perry, Longoria, Magic Johnson, Jon Hamm, Kelsey Grammer, Jon Voight, John Ratzenberger, Zach Galifianakis, Ed Helms and others "have all graced the Silver State to stum! p for Barack Obama and Mitt Romney."

"Presidential candidates are soooo pedestrian," according to the Sun. "Or at least it seems that way, given how the parties have been amping up their Nevada campaign events with stars that may count as more A-list than the potential leader of the free world."