Pictures: Rihanna Forgets Pants, Risks Wardrobe Malfunction at iHeartRadio Festival:

Singer Rihanna performs onstage during the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 21, 2012 in Las Vegas, Nevada. (Source: Christopher Polk/Getty Images North America)
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Rihanna (Christopher Polk/Getty Images North America)
Rihanna perhaps forgot to put on her pants before taking the stage at the iHeartRadio Music Festival Friday night in Las Vegas. The singer came out to perform in the shortest, sparkliest gold jersey imaginable, without anything on the bottom.
The singer is known for her risque ensembles, but her golden jersey was definitely cutting it close to a wardrobe malfunction right off the bat. But, she managed to keep it modest for her performance.
The sold-out crowd in Sin City loved her show and got a real treat when they also got to see Green Day's Billie Joe Armstrong lose it onstage. The rocker went on an F-bomb filled rant, which even included a Justin Bieber reference, after the band's set was cut short, allegedly to give Usher more time to perform. Armstrong then went a bit sideways and ended up smashing his guitar at the end of his angry monologue. It's unclear if the star was really THAT mad or just wanted to show the other pop stars how to be a real "rockstar."
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Singer Rihanna performs onstage during the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 21, 2012 in Las Vegas, Nevada. (Getty Images)
more pics »
Singer Rihanna performs onstage during the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 21, 2012 in Las Vegas, Nevada. (Getty Images)
more pics »
Singer Rihanna performs onstage during the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena on September 21, 2012 in Las Vegas, Nevada. (Getty Images)
more pics »