HotStar: fun.

Nate Ruess, the frontman and songwriter of fun., is having a lot more of it these days with the band that he formed with friends Andrew Dost and Jack Antonoff after his previous group, The Format, dissolved in 2008.

The change clearly suited him, as fun. released its first single, “At Least I’m Not As Sad (As I Used to Be)” within months of the demise of The Format. The band was soon plying its trade on the road, with a much-coveted opening slot opening a tour for Jack’s Mannequin before the release of its first album, Aim and Ignite.

Three years later, fun. is riding high on a new album, Some Nights, a hit single, “We Are Young,” its first release on Fueled By Ramen, and a much buzzed-about appearance at South by Southwest in March.

But it was hardly the band’s first splash of the year. That came in the form of a Super Bowl ad for Chevrolet that was the topic of much water cooler chatter. “We Are Young,” which features a guest vocal by Janelle Monae, provided the soundtrack to the “Stunt Anthem” ad that was overshadowed only by a fellow named Clint Eastwood.

Ruess, multi-instrumentalist Dost and guitarist/trumpeter Antonoff form the core of fun., with three other musicians rounding out the touring band. Under the guidance of manager Dalton Sim of Nettwerk Management and agent Matt Galle of Paradigm, fun. is blowing up in 2012.

After some well-placed opening slots with Paramore and Panic! at the Disco, fun. is headlining its own outing. As recently as March, fun. was selling out respectably sized clubs in the 300- to 500-capacity range. But thanks in part to a lot of SXSW buzz and a well-orchestrated campaign, those days are over.

From playing to 450 in Alabama in March to a two-night stand just last week at the 9:30 Club in Washington, D.C., the fun. is just beginning. The band is hitting the road for summer, including festival stops such as Bonnaroo and Lollapalooza, and 1,000-seaters and up like Terminal 5 in New York City.