Imagine Dragons blew up in 2012, spearheaded by their hit "It's Time."

Ironically, the song that would become Imagine Dragons' most recognizable tune to date was written during a time of transition, when the band had doubts about its future.

"It's kind of interesting the way that works out," said Imagine Dragons' lead guitarist, Wayne Sermon. "A lot of times, when things seem the roughest or when life seems the most hopeless, maybe that's the best times of inspiration, of creativity, for whatever reason."

The group performs Friday at the Fillmore in Silver Spring. The show is sold out.

In concert
Imagine Dragons
» Where: The Fillmore Silver Spring, 8656 Colesville Road, Silver Spring
» When: 8 p.m. Friday
» Info: Sold out, but tickets may be available through resellers; 301-960-9999;

To some, Imagine Dragons' success may seem like it came overnight, but in reality, the band toiled for more than three years in Las Vegas. By playing marathon six-hour sets full of covers for a few hundred dollars in small casinos, Imagine Dragons refined their sound and perfected their chops.

"For us, it wasn't sudden, really," Sermon said, speaking from a tour stop in Atlanta. "We felt pretty strongly from the beginning to do it a certain way. We wanted to do a grassroots-type thing as much as we possibly could. We felt you have to build a core group of listeners that will be with you. Come hell or high water, they're going to be your fans for life. It's important to build that core and to earn that on your own. That's how we definitely chose to do it.

"It's really in the last year that it's started to pick up, which is where the sudden part comes in," Sermon continued. "In a sense, it is sudden because you slave away for those three years and no one knows who you are and you're not always the most hopeful that things are going to happen. It's a snowball effect, really. It's not something you can ever expect. You never know what's going to happen in this industry."

The song "It's Time" has garnered plenty of radio play, as well as multiple television and other media placements. Imagine Dragons' debut album, "Night Visions," is a collection of big rockers covering the scope of emotion, from desperation to empowerment.

With their new album gaining steam and "It's Time" giving way to new singles such as "Radioactive," Sermon said Imagine Dragons will continue to do what they know best: playing live, hearkening back to those smoke-filled casino days.

"We feel like our live show is sort of our bread and better," Sermon said. "We feel like that's what we do best and feel like people will understand if they see us live."