The Griswolds’ first bio simply read: “The chameleons of pop.” That description holds true for the Sydney indie pop group, formed almost two years ago by singer/guitarist Christopher Whitehall and lead guitarist Daniel Duque-Perez, as they look to become a globally known act.

The Griswolds were thrown into the spotlight immediately after they found instant success in early 2012 when they became Australia’s Triple J “Unearthed” feature artist and won a slot on the 2012 Parklife Festival lineup alongside Passion Pit. In the beginning there was no set plan for the music, which was created almost incidentally by the joint efforts of the duo. The two musicians had been playing in various bands around Sydney and got together one night to expand on a guitar riff Dan had written. That was when they knew almost immediately, they had great songwriting chemistry.

“At the very beginning, you don’t really know what to expect and don’t really know what the potential is with a new project,” Christopher said. “There was some skepticism about what we would do with it, but after we wrote a few songs together it was clear that this was something special. These weren’t just good songs; they were some of the best songs we’ve ever written.”

That riff evolved into a song called “Mississippi,” which later became the band’s first hit in Australia. “Mississippi,” and its buoyant, upbeat melody, sing-along chorus and group vocals embrace the exuberant tone the musicians wanted to pursue with The Griswolds.

The Griswolds’ lineup is rounded out by bassist Tim John and drummer Chris Riley. They self-recorded and released their debut Heart of a Lion EP in Australia during the fall of 2012 without actually having a band name yet. After a long late night conversation, the name The Griswolds came up through their mutual love for National Lampoon’s Vacation film series and it stuck. The EP, a shimmering four-song collection of tropical indie pop numbers, immediately earned them notable accolades from press and fans alike will be released in the United States on September 3, 2013.

All of the songs were written and produced by Whitehall and Duque-Perez and were recorded in the musicians’ house as well as a studio in Sydney throughout 2012. They selected the four best songs they’d written to comprise their first EP release. “We decided to go all-in,” Christopher says. “We just wanted to write the best songs and then make it work. And we got lucky. The guys who are in the band are all amazing musicians.”

“Heart of a Lion,” the single, with its charming and buoyant toe-tapping sounds, has received airplay in over 20 countries worldwide. The track was also featured as an iTunes “Single of the Week” and notably created a huge buzz in the Netherlands, where it reached No. 3 in radio airplay.

The Griswolds have toured extensively in Australia, Europe and the U.S. with artists such as, Django Django, San Cisco and Last Dinosaurs to name a few and played numerous Australian festivals including Big Day Out, a show that stands out in their minds as their favorite show to date. “It was 48 degrees Celsius and it was early in the day but when we walked out to the stage the crowd was enormous, over 2000 people all screaming the words back at us,” said Dan, “and best of all was that it was in our home city.”

They plan to expand their aesthetic on their debut album, which they will record with Tony Hoffer in LA in January 2014. It will be released later this year and will showcase the band’s growth since recording their EP. And now with the EP coming out in the States on Wind-up Records, The Griswolds have started thinking beyond making songs with no real intention. Everything, though, still goes back to the two guys who connected over a guitar riff.

“Back when we wrote the EP it was two guys in a house writing songs for fun and not really knowing who was going to be listening to it,” Christopher says. “We wrote for fun and for us and for Australia and that was great. Now we’re getting a lot more ambitious and we’re thinking globally. But we want to stay true to ourselves. I think our style of music all comes down to big choruses you can sing along to.”