Rihanna - iHeartRadio Music Festival: Rihanna hits the stage in Jeremy Scott as she closes out Day 1 of the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena on Friday night (September 21) in Las Vegas. The 24-year-old singer performed some of her most recent hits including “We Found Love,” “Birthday Cake,” and “Where Have You Been,” as well as a few of her older songs including “Only Girl in the World,” “Don’t Stop The Music,” and “Umbrella”.