Around 6:00 p.m. on Saturday, the backstage of the Mann grew quiet.

Before a concert, the Mann is usually abuzz, sometimes even hectic, before a performance begins. But Saturday was different. Instead of employees rushing around backstage to ensure that the show goes smoothly, secret service agents milled about, sealing off the entrances and permitting only people with high clearance into the regulated area.

Hillary Clinton was set to arrive.

Outside, employees and patrons buzzed, waiting for the event's performances to begin. The surprise concert was announced just five days in advance as part of Clinton's "Get Out and Vote" campaign concert series. Several politicians spoke on Clinton's behalf, and pop star Katy Perry performed in front of a crowd of 8,000 people. Perry has publicly been an avid supporter of Clinton since last October when she endorsed the Presidential candidate. This is not the first time she has performed to campaign for Clinton — in October of 2015, she headlined a major rally in Iowa.

According to the Philadelphia Inquirer, before performing on Saturday, Perry explained, "I admire so many things about Hilly C. I agree with so many of her informed, educated policies. And no matter who you are or where you come from, she will be a president for all of us."

Perry performed her hit song "Roar" among others, wearing at first a cloak that said, "I'm with Madam President," before taking it off to reveal a sequin dress in the design of an American flag.

Many celebrities have endorsed Clinton, including Beyonce, Jay Z, Meryl Streep, Madonna and Lena Dunham. U.S. Senator Bob Casey spoke briefly on Clinton's behalf, informing the audience about a rally on Monday, November 7, with Hillary and Bill Clinton, Chelsea Clinton, Barack and Michelle Obama and Jon Bon Jovi. U.S. Senator Cory Booker gave a fiery speech about the poverty line and rights pertaining to gay marriage and abortion.

"We have to understand in America that we can not accept folks that want to sit on the sideline," said Booker. "We can not accept people who do not get the emerged urgency of this moment. This election is going to determine the outcome of people's lives. How privileged are you to think it does not matter?"

He continued, "We have a purpose here tonight because we still have a nation that — just because of who you choose to love you — in most states in America you can be fired from your job because you're gay with no legal recourse."

Former Secretary of State, Madeleine Albright, also spoke at the event.

"Nobody has ever been as prepared to be president as Hillary Clinton," Albright said. "We are a great democracy. I am a naturalized American, and I am grateful to be an American. The most importance responsibility of America and American citizenship is to vote, and you are the ones who are going to make that happen by telling friends and neighbors that their vote will make all the difference, that we will have a great president."

"I have to say, if you noticed my pin," she said, pointing just below her shoulder, "that it is shattering the glass ceiling, and that is what Hillary is going to do with your help. Thank you, we're gonna do it!"

TV producer Shonda Rhimes made an appearance at the concert as well, saying that she couldn't have created a more fierce female character than Clinton. Clinton herself then spoke to the audience about the current election, "I think we are really going to send a message from coast to coast, east to west, north to south, about who we are as a country. And if we do what we should, then on November 9, this coming Wednesday, we can all wake up and say, 'I'm gonna do my part to make sure that America lives up to its promise to every one of our people, especially every one of our children, who deserve the chance to live up to their god-given potential.'"

Both Clinton and Trump have held rallies in Pennsylvania in the past week, Clinton in Philadelphia and Trump in Hershey. The presidential candidates are campaigning hard in the last couple days of the 2016 election, one which still looks like a close race.