Armstrong on stage in Melbourne. Credit:Michael Clayton-Jones "From a personal point of view, there were doubts [about our future, but] my friends' lives come before the band. As much as the band is part of our lives . . . we have to be healthy – mentally and physically – and what we do on stage is not easy, it carries a lot of responsibility, and it carries a lot of physical stress and mental stress. At this point, [Green Day] is held to a higher bar than we would have been a long time ago." Dirnt says that before Armstrong's meltdown, Green Day hadn't really stopped for 20 years. "We hadn't taken a vacation, hadn't looked up, hadn't done anything that wasn't writing music and touring. When you're working that hard, there's a lot of down time on the road. You can drink too much or get into sleeping pills or whatever, but at some point, you have to step up and make sure the person that you are is the [best] part of you." Armstrong spent months in rehab and Green Day resumed touring in March. They've played 47 shows since, the latest being the Leeds Festival, which Britain's Guardian called "a masterclass". Dirnt says Green Day is back to its best. "It's pretty awesome right now. Before it was tense . . . it was chaos [touring the world after] coming right out of recording [Uno, Dos and Tre]. Now we've had time to let the dust settle and get our shit together, we're ready to tour and play. [But] we're going to take some breaks in between so we don't kill ourselves. It's important for this band to make more records."

The real deal: Johnny Rotten. Credit:Richard E. Aaron With the band firing on all cylinders, Dirnt relishes mixing it up at Soundwave in February, a rare chance to be part of a wall-to-wall hard-rock festival. "It's more appealing to me [than a festival where] there's a techno tent next to me while I'm trying to play," he says. "I'm all for diversity, but I'm not really into stupidity; sometimes shows are booked kinda stupid. A lot of fans don't want [that]. "Soundwave has its own identity, it's like a [rock] mecca to go to." Dirnt wasn't sure if Green Day would play their huge breakthrough album, Dookie, which turns 20 in 2014, as they did at the Reading and Leeds festivals last month. At Reading, the band covered the Ramones' Blitzkreig Bop and AC/DC's Highway to Hell – which they could do again.

I'm just a dirty white boy that wants to play his f---ing music in whatever shitty fashion I can. "It's an anthem and that's what it's all about. That's us tipping our hat [to AC/DC]," Dirnt says of the band he credits with being one of his two formative music experiences. "In 10th grade I remember trading my bicycle for a weekend to borrow the cassette tape of Back in Black . . . and that was awesome." The other record that shaped Dirnt's musical outlook may disappoint some fans, but it has that same spirit: It's Still Rock and Roll to Me by Billy Joel. You could argue that Green Day's recipe for success is summed up in those two song choices: an uncompromising rock classic and a chart-topping pop track for the masses. To balance, for two decades, being true to the rebelliousness of punk while making catchy records that sell is quite an achievement. Does Dirnt feel a sense of responsibility to be faithful to the original punk ethos? "I feel a responsibility to be faithful to myself," he says. "If that sounds narcissistic, I know where I come from; I need to be who I am . . . I keep one foot in the gutter. Sometimes, I want to put the other foot on a mountain. And I don't think there's anything wrong with that.

"[But] at the end of the day, I'm just a dirty white boy that wants to play his f---ing music in whatever shitty fashion I can." Green Day will headline Soundwave music festival in February 2014. Do you feel lucky, punk?

Warning: this video has strong language. Green Day are sometimes criticised for not being true punks. Let's face it: there's a big difference between pioneering punks the Stooges and today's chart-topping pop-punk, made by the likes of Blink-182.

So are Green Day still punk? Or are they cashing in on the corporatisation of a type of music that at heart is pure anti-establishment? It's hard to criticise the band's commercial success when punk's origins lie in pop music and so many influential punk acts wanted to make accessible music. One of the most influential acts in the genre (the Sonics) had frenzied popularity among local kids in America's north-west in the early 1960s. A decade later, the Ramones, so closely associated with the punk ethos, essentially made 1950s teen songs played at a faster tempo. (In songs like I Wanna Be Your Boyfriend or Rock'n'roll High School you'll hear the beginnings of pop-punk.) In Britain, the Sex Pistols, led by Johnny Rotten (pictured), might have looked scary and dissed the monarchy, but the band's guru, Malcolm McLaren, set out to create a popular music phenomenon. There's no doubt the growth of the punk movement was partly a reaction to the excess of 1970s rock, and the songs were faster, more aggressive and stripped-back than other music. Yet it could also be argued punk's rebelliousness was mostly a fashion in the 1970s. The perception of punk as antithetical to the mainstream grew out of the second wave of punk, in the late 1970s and early 1980s, when punk sub-genres multiplied and hardcore bands sprung up in the US and Britain, many of which became associated with niche political and social values. In the US, Black Flag was concerned with social isolation and a DIY ethos, the Dead Kennedys were anti-conservative, while in Britain, ''street punk'' emerged (led by bands such as Sham 69).

The punk revivalists of the 1990s, such as Green Day, reinterpreted the punk they grew up with and succeeded in bringing it to the masses. PV