LONDON, United Kingdom—Pop fluff or bona fide rockers? Australian pop-punk sensation 5 Seconds of Summer have gone from YouTube fame to a world tour, with a follow-up to their hit debut album out Friday.

READ: One Direction announces album after split speculation

The four young men from Sydney, who reject any comparison to the British boy band One Direction, say they are going for a darker, deeper sound in their new album “Sounds Good Feels Good.”

“There’s a lot of people that have influenced us. Anyone from Queen, INXS, endless rock bands and classic rock,” 21-year-old drummer Ashton Irwin, the oldest of the group, told AFP in an interview.

“That was something we really struggled with when we went into the studio because we want to sound like a lot of things,” he said.

Sporting skinny black jeans, black boots and messy hair, the band spoke about their dizzying rise, the mixed reviews they have received and the determination needed for a music career.

“If you think you have something special and different that no one else can offer, which is what we thought we had, stick to it, and don’t let anyone touch your baby,” said 19-year-old guitarist and singer Luke Hemmings, explaining the group’s success.

READ: Nick Jonas hosts the Nickelodeon’s 28th Kids’ Choice Awards on March 28

With their shiny, radio-friendly guitar-laden pop comparable to US punk acts Green Day and Blink-182, the band has sold 3.2 million copies of their eponymous debut album since they formed in 2011.

Their rise has been accompanied by critical acclaim—they were named “Best International Newcomer” by rock magazine Kerrang!, “New Artist of the Year” by the American Music Awards and have earned a number of MTV accolades.

They also received the dubious distinction of “Worst Band” at music weekly NME’s annual awards this year.

“We’re doing something maybe that challenges people’s thoughts, and that’s the best thing a band could do I think,” said Irwin, commenting on the NME “award.”

Not a boy band

The group’s chart-topping debut single last year “She Looks So Perfect” with the hook “She looks so perfect standing there, in my American Apparel underwear” reportedly triggered a spike in the US brand’s sales.

It has since been a whirlwind of touring, packed gigs and TV talk show appearances for the band, which once considered calling themselves “Bromance.”

Their new album is already at number one on iTunes music charts in 54 countries based on pre-orders alone.

It has a darker tone than the first, the mood partly reflecting the highs and lows of being on tour, which 19-year-old guitarist Michael Clifford described as sometimes being “like a robot.”

“Now that I’m broken, now that you know it, caught up in a moment, can you see inside?” he sings on the new album’s “Jet Black Heart.”

“I think our new album is less upbeat… Some of our songs are pretty deep these days,” Hemmings said.

Unlike One Direction, a group put together by music moguls and paraded on a TV talent show, 5 Seconds of Summer, or 5SOS, met in school, and were first noticed through videos they posted of themselves playing covers on YouTube.

Comparisons are inevitable given the band have toured with One Direction and are managed by the same company, but fans make a clear distinction.

“We don’t see them as a boy band, they play their own instruments,” said 21-year-old Iren Coutiel, one of a group of girls waiting outside the trendy east London office where 5SOS were holding interviews.