Katy Perry performs at the Kid's Inaugural in Washington.

Katy Perry performs at the Kid’s Inaugural in Washington.

Katy Perry saluted the flag with a hot stars and stripes bodysuit as she performed for the Kids’ Inaugural Concert in Washington, D.C. She was joined by R&B crooner Usher, while First Lady Michelle Obama and kids Malia and Sasha looked on.

Bands Mindless Behavior and Far East Movement and “Glee” cast members Darren Criss, Naya Rivera and Amber Riley joined them on stage.

The Wanted and stars from Disney Channel’s “Shake It Up” and Nickelodeon’s “Big Time Rush” appeared via video link.

Michelle Obama had this to say: “You see, when we said we wanted to host a concert to honor our military kids, let me tell you, everyone wanted to be here. Usher wanted to be here, Katy Perry wanted to be here. Nick Cannon, the folks from Glee, and all the other amazing performers — they wanted to be here, too. And let me tell you, they’re not here for me. They’re not here for Dr. Biden. They are here for all of you. Because they know the kind of sacrifices that you all make every single day.”

“America’s Got Talent” host Nick Cannon, who emceed the Saturday (Jan. 19) show, but Ms. Obama called out Katy. The 28-year-old singer was dressed like a World War II-era pinup, in the sparkly red, white and blue outfit. She performed her hit “Firework.”

Amber sang Christina Aguilera’s moving anthem “Beautiful.”

As many as 800,000 people will attend Monday’s public ceremonies to usher in President Obama’s second term. About 1.8 million attended the historic first inauguration in 2009.

Check out performances by Katy and Glee cast members below, watch Michelle Obama address the audience and be sure to follow TheImproper on Twitter for more celebrity updates.