Katy Perry Crashes Prom

Katy Perry crashed the Melbourne High School formal at the Grand Hyatt when she heard her hit, "California Gurls" come on.

Katy Perry crashed a high school prom in Australia when she heard her song "California Gurls" being played.

Katy was staying at the Grand Hyatt hotel in Melbourne during her Australian tour.

She reportedly wowed the crowed when she grabbed the microphone and started singing along with her own song!