Clarkson once said she was a fan of Republican presidential candidate Ron Paul, but she says she voted for Obama twice. She'll perform "My Country `Tis of Thee" at Obama and Vice President Joe Biden's swearing in ceremony Monday after Obama takes the oath of office.
"We came up with a really cool arrangement for it and I really love the lyrics," she said.
Beyonce will sing the national anthem and James Taylor will sing "America the Beautiful" on the West Front of the Capitol on Monday. Both performers are regular Obama supporters, and celebrities have been a big part of Obama's strategy to attract voters. Bruce Springsteen is a regular supporter, as is Lena Dunham, Scarlett Johansson, Jay-Z and dozens and dozens of others.
Pop-rock trio fun., who had a wild year with two No. 1 hits, a near-platinum album and six Grammy nominations, will perform for first lady Michelle Obama, Sasha and Malia and Jill Biden on Saturday at the Kids' Inaugural Ball.
"It's been amazing year, and 2013 is kicking off with us doing the inauguration ... it's just an incredible thing," said lead singer Nate Ruess. "I think the three of us care so much about Obama and so to be invited, I can't even deal."
Fun. will be joined at the concert by Perry, Wonder, Keys, Usher, Smokey Robinson, Paisley, Marc Anthony, Mindless Behavior, Nick Cannon and the cast of "Glee."
"I think they're all very talented people. Stevie's my brother and so is Usher," Robinson said in an interview. "I know Katy ... I'm very happy to be performing among them."
While there will be no shortage of star power, it's not quite a repeat of the 2009 inauguration when everyone who's anyone flocked to Washington for a televised concert on the Mall.
The first time around, Beyonce was a surprise guest, singing the Etta James classic "At Last" for the first dance. Her husband, Jay-Z, was another surprise at the private staff ball, singing "99 Problems but George Bush Ain't One." The Jonas Brothers - then favorites of the Obama girls - performed at the kids' concert and U2, Springsteen and so many others performed on the Mall.
There may still be surprises in store, but plenty of performances are assured. Keys, Paisley, Chris Cornell, Jamie Foxx, Jennifer Hudson and Anthony will perform at the Commander-in-Chief's Ball on Monday.
Will.i.am, who debuted the song "New Day" at 2009's inauguration, will be at a number of events, including OurTime.org's "General Now Party" on Saturday, which also includes John Legend, Jessica Alba, Common and Flo Rida. Eva Longoria will host the "In Performance at the Kennedy Center" event, which celebrates Latino arts and culture, and will feature Antonio Banderas and Rosario Dawson. And 25-year-old pop party girl Ke$ha will perform a charity concert Monday.
The Creative Coalition will host parties Sunday and Monday that is expected to include Eric Stonestreet, Connie Britton, Taraji P. Henson, Melissa Leo and David Arquette, among others.
Like will.i.am, soul crooner Legend will attend multiple events, including Russell Simmons' Hip-Hop Inaugural Ball II with 2 Chainz, Brandy and Pharrell. BET also has a ball that comedian-actor Wayne Brady will host; performers include Bell Biv Devoe, Doug E. Fresh, MC Lyte and Jermaine Dupri. And Pharrell will host an event late Monday that supports education.
Clarkson says she continues to gush when she thinks about all that's going on to celebrate Obama's second term in office.
"I'm excited to be a part of it honestly. I'm more stoked about (it more) than maybe a lot in my career," she said.