What goes on in Vegas most certainly will NOT stay in Vegas here!
Watch it go down (below)!!!
Katy Perry ALWAYS entertains when she performs, and this is no different.
The singer let her vocals roar during the first ever performance of Dark Horse!
And that wasn't all because she also had Juicy J on hand to do his part at the iHeartRadio Music Festival in Las Vegas.
There might not be any wild animals involved in this performance, but Katy still slays it!
And that song? It's getting damn catchy!
Check out more pics of Katy from the festival (below)!
[Image via DJDM/WENN.]