Transcript for Imagine Dragons' Fast Rise to Fame
For a bunch of rock stars, the members of imagine dragons are surprisingly down to Earth. They may win grammys but nobody's keeping their dressing rooms at a perfect 72 degrees or picking out all the green m&ms. Tonight these chart-topping musicians are returning to their hometown to say thank you. A little place you might have heard of called Las Vegas. Here's ABC's Rachel smith. ? ? I'm on top of the world heh ? Reporter: Feeling on top of the world isn't just a catchy lyric for this band. Hitmakers imagine dragons seem to have the formula down for chart-topping pop rock anthems like "Radioactive." ? Welcome to the new age welcome to the new age the new age ? How does it feel? Essentially being on top of the world? Every day, we still go onstage thinking, really? Are 20,000 people coming to see us tonight? And they come. You have the piano bar right there. Reporter: They started booking gigs in small Las Vegas bars, struggling to make ends meet. We did play the salon of beauty right there. Maybe they'll let us in. Reporter: A few years later they're selling out stadiums. Vegas kept us alive because we went to the hotels and begged to play their lounges. They said, if you earn 100 covers we'll let you do a six-hour stint and pay you a little bit of money, enough to survive and eat Lima beans, ramen. Reporter: These once-starving artists invited me back to their hometown fare a surprise charity concert right on the Vegas strip, benefiting music programs at local schools. Imagine dragons! Now we're en route to their secret show. Don't really know much about it. Hence, secret. They're going to do about three songs. ? Whoo whoo whoo ? ? so I buiet my life ? Reporter: Performing the hit song "I bet my life." They come across like the ultimate un-rock stars, who say they aren't motivated by the awards and fame. You've seen bands come and go for any number of reasons. Whether drug abuse, relationships within the band are deteriorating. Yeah, we just want to avoid all of that for as long as we possibly can. It was never I want to join a rock band to get girls, to be popular. It really was literally because we love music. ? I feel it in my bones ? Reporter: It seems fame keeps finding them. ? Welcome to the new age to the new age ? Reporter: Netting a grammy last year for best rock performance. ? When you feel my need look into my eyes ? Reporter: Rocking the big stage at the American music awards. ? It's when my demon's high ? Reporter: "Night vision" making to it two on the billboard charts. "Smoking mirrors" releasing later this month is already getting buzz. What is the creative process like with it? Our lives have changed in a lot of ways in the last couple of years so that finds its way into the record. We've had so many highs and lows. You lose a lot of friends along the way because you -- you're never home. Then you make a lot of false friends along the way because suddenly your band's successful. I feel like it captures the emotions of a young band that has gone through what we've gone through, which is a lot of crazy transitions. ? Radioactive, radioactive ? Reporter: Back on the strip, performing "Radioactive," they seem truly grateful to these hometown fans that set off the wild ride to stardom they hope is just beginning. We love you, Las Vegas! Reporter: For "Nightline," I'm Rachel smith in Las Vegas. Good for them. It's a reminder of what's been said. There are only two kinds of people on this Earth. Those who are humble, and those who will be humbled.
This transcript has been automatically generated and may not be 100% accurate.