The iHeartRadio Music Festival is the largest live music event in radio history held at the MGM Grand Garden Arena in Las Vegas, Nevada.
The night featured acts from several artists, including Jay-Z, Usher, Bruno Mars, Jennifer Lopez, Nicki Minaj, and Lady Gaga. There was a special stage built specifically for Gaga's performance. Justin Timberlake introduced Lady Gaga.
Gaga named this performance a "Surrogate Monster Ball" referencing the tour's arrangements of the songs from the setlist. Despite going over her allotted 45 minutes of performance time, Gaga joked with the crowd about her long sets: “They told me I was only allowed to play for 45 minutes. But I think you’re all pretty drunk so you probably don’t know what time it is do you?”