Katy Perry Rocks At the Kids' Inaugural Concert!

Katy Perry, Usher, and some of the cast of Glee shared the stage at the Kids' Inaugural Concert on Saturday night!

President Obama and his wife Michelle, as well as their daughters Sasha and Malia attended the concert, as well as hundreds of children from military families and children from local schools in Washington D.C.!

Check out Katy's performance of her hit "Part Of Me" above!