Question: A three hour music festival at the 2017 Teen Choice Awards was hosted by an actor who rose to fame on what video application?
Sentence (from "2017 Teen Choice Awards"): Throughout the show, several celebrities, including Vanessa Hudgens, Zendaya and Lauren Jauregui of Fifth Harmony, addressed the aftermath of the 2017 Unite the Right rally and encouraged teens to speak out against violence and hate.
Relevant evidence: No