The pop star treated fans to the first-ever performance of her new song Focus at the iHeartRadio Theater in Burbank, and sat down for a question and answer session after the Halloween gig, during which she was dressed as a female Jack Skellington from The Nightmare Before Christmas.

However, the chat was briefly disrupted when a smart phone was hurled at the platform. No one was injured, and Ariana remained poised as she brushed off the incident.

In video footage posted online, Ariana can be seen addressing the crowd, saying, "Did someone throw a phone at me? Did someone just throw a phone on stage? That's so dangerous."

"What if your screen cracked?" she quipped.

The phone was subsequently retrieved and Ariana helped to locate its owner, warning them, "Be careful. Take your phone back."

It is not known if the fan intentionally threw the phone or accidentally let go of it as they waved their arms in excitement.