On "Take Your Time (Coming Home)," a track of Fun.'s debut album Aim and Ignite, singer Nate Ruess gently croons, "I'm just a boy inside a voice."
After seeing the nimble frontman perform live in front of a small, intimate iHeartRadio crowd in New York City, I now understand what he was talking about.
When he's performing, Ruess is like a tiny ball of energy, enthusiastically jumping around the stage and amping up the crowd with natural bravado. However, in between songs, you get the sense that the Fun. frontman really is just a boy inside of a booming voice. He's quite shy on stage, but luckily, he has his bandmate, guitarist Jack Antonoff, to help entertain the crowd.
"I'm the biggest Fun. fan ever!," a girl near the stage shouted after Fun. kicked off their short set with "One Foot," a hip hop-influenced track off their latest album Some Nights.
"Oh, yeah?," questioned Antonoff. "Where was Nate born?" When the flustered fan couldn't come up with an answer, he jokingly responded, "You're the least biggest fan ever," to which Ruess aptly replied, "Let's just start the track."
In case you were wondering, Ruess was born in Iowa.
It seems ironic that not one fan knew where the frontman of the band with the No. 2 song in the country -- "We Are Young" actually topped the charts for six consecutive weeks before being knocked down by Gotye -- was born, but in some ways, it's fitting.
Fun. is a relative newcomer to the Billboard charts. Formed in New York City in 2008, the band was a new beginning for lead singer Ruess. The singer, who had recently left The Format, was joined by Andrew Dost of Anathallo, and Antonoff of Steel Train.
Though the band mostly played tracks off Some Nights -- arguably the more successful of their two studio releases -- they did play one song for loyal Fun. fans: 2010's "Walking the Dog." He attacked the old-school track with feverish excitement, as the lights flashed behind him. When the song ended, the lights went black and the stage was silent, almost as if Ruess had become invisible. Then, when the drumbeat kicked back in, he was back to his old ways -- throwing his microphone in the air, skipping around the stage and wailing at the top of his lungs.
During the set, Ruess, decked out in a yellow Fun. t-shirt, showcased his incredible vocal ability, especially on the slow-tempo track "Carry On," in which the singer's voice was left to to stand on its own, without their signature heavy beats and production.
"If you're lost and alone / Or you're sinking like a stone / Carry on," Ruess softly sang as the lights dimmed, before bursting into the a swelling second verse.
After finishing their power ballad, Fun. launched right into their hit track "We Are Young," and it became overwhelmingly apparent why everyone was really there. The band didn't need to say a word -- the opening drumbeat kicked in and the iHeartRadio crowd went wild. For the first time during their short set, the band truly thrived off the audience's excitement.
Jon Bon Jovi was even seen enjoying the show from afar in the VIP section.
The band then closed their set with their title track "Some Nights," which featured some of Ruess' best vocals of the night. His voiced seemed infinitely bigger than the tiny frontman on stage, and the band's musical eclectic arrangement brought the catchy pop melodies to life.
By the end of the night, Fun. did what any band aims to do during a live show: They left the audience wanting more.
(Also, kudos to Fun. for not opening their set with, "Are you guys ready to have some fun tonight?")
PHOTOS: Fun. performs in New York City for an iHeartRadio set