With more than 40 perfomers including Fetty Wap, Nicki Minaj, Justin Bieber, Skrillex and X Ambassadors, theBillboard Hot 100 Music Festival was the place to be this weekend. And the celebrities performing were just as excited to be there as the fans. Here, we round up the best performance and behind-the-scenes photos to give an insider look. Related: How x Ambassadors took over the alt-rock scene Related: How Justin Bieber made a comeback Follow Emily on Twitter: @EmLaurence