They knew that "It's Time" was going to play on the radio that day, but they weren't quite sure when. They weren't even sure if they'd be able to get the station on their car stereo since they were so far out of range.

Immediately after the shoot wrapped, the four guys got into a car and booked it back to Los Angeles. "We were driving as quickly as possible and we managed to hear the second chorus through the static," bassist Ben McKee told Radio.com hours before the band took the stage at Lollapalooza. "It's a moment I think we'll never forget."

Frontman Dan Reynolds agreed: "I don't think any of us expected last year to blow up exponentially like this, but I think we're all just delightfully surprised."

While they've only released one record, the Las Vegas-based band has been around since 2008 playing shows along the Vegas strip. The shows, which were half originals, half covers, barely paid them enough money to cover their rent.