Katy Perry Roars With Ellie Goulding, Sara Bareilles, And ALL Her Fans! See The Epic Musical Moment HERE!

As if Katy Perry‘s roar wasn’t loud enough!

The powerhouse got some very talented help for her live performance of Roar at the Hollywood Bowl last night!

The night of AHmazing music in the outdoor theater ended with a purrrrrfect collaboration of vocals between Tegan And Sara, Ellie Goulding, Sara Bareilles, Kacey Musgraves, and her songwriting partner Bonnie McKee.

Can you say girl power??!

Ch-ch-check out the once-in-a-lifetime rendition…AFTER THE JUMP!!!