JUST ADDED: 5 Seconds of Summer will be rocking the stage at this year's iHeartRadio Music Festival Village in Las Vegas! The band sat down with Ryan Seacrest to break the news. Click here to buy your tickets now, before they sell out!
When Justin Bieber told 'GQ' magazine that he was a Metallica fan last year, he wasn't kidding.
The pop star was caught on video playing air guitar and using his voice to cover Kirk Hammett's guitar solo from the band's song "Fade to Black" - a song that came out 10 years before the Bieb was even born.
Watch him rock the air guitar below: