THE only person who wasn't surprised when Phil Jamieson accepted the invitation to enter the world of musical theatre was the Grinspoon frontman.
When he got the offer to play St Jimmy in the Green Day musical American Idiot, Jamieson gave a resounding "Hell yeah!" even as his team raised a quizzical eyebrow.
"I said 'We are doing this!' Some people were a bit dumbfounded by that. The fact I was asked suggested people are willing to take a risk," he says.
The risk paid off when Jamieson shared the pivotal role with The Living End's Chris Cheney in the premiere production of American Idiot in Brisbane earlier this year.
It has now been booked for a national tour which kicks off at the Sydney Opera House in January.
Cheney isn't available for the tour so Jamieson owns the role in the award-winning production's national run next year.
The respected rocker said he was initially terrified by the challenges of the move from the concert stage to the theatre.
"Rock'n'roll isn't particularly disciplined and I haven't been in the past," he says, laughing.
"There's warming up your voice and warming down and literally not a drop of alcohol backstage.
"Learning to play a character was another discipline and there was a bit of a steep learning curve about props.
"In rock'n'roll, the spotlight follows you but in theatre, the spotlight stays fixed and you have to hit your mark."
Jamieson suspects Green Day frontman Billie Joe Armstrong always intended for their 2004 punk opera record to become a musical.
That ambitious opus arrived at a time when punk rock songs ran just over a couple of minutes. Armstrong challenged the status quo with Jesus Of Suburbia and Homecoming which ran over nine minutes and featured five movements. It was as close to a classical piece as punk rock could get.
The musical takes those songs and others from the American band's considerable repertoire to tell the story of three lifelong friends Johnny, Will and Tunny who are struggling to break out of their suburban rut.
"When you see it on stage, you wonder if it was in the back of Billie Joe's mind the while time," he says.
"It was obviously a rock opera originally and to see it come to life, it is pretty mind-blowing that he had the tenacity and the balls to write that record at a time when punk rock was doing two minute songs and he was doing nine minutes and all those different parts."
Armstrong wrote the record as a post 9/11 reaction to the conservative politics of President George W. Bush. Its Australian production arrives as the world struggles to negotiate the chaos of Donald Trump's presidency.
Jamieson says there is no way to avoid the political undercurrents of this story of three lost souls trying to negotiate life in the media-saturated new millennium.
"This was written around the George W. Bush administration and anyone could draw parallels between then and now," he says.
"But I'll let the audience be the judge of that; I don't want to give (Trump) more oxygen than he has."
Jamieson cheekily describes American Idiot as a "gateway musical", a production to entice Grinspoon fans to the theatre perhaps for the first time.
Among those who saw his performance in the Brisbane shows earlier this year were his daughters Lyla and Evita who are both keen actors in their high school musicals.
While he tries his best to keep his swearing to a minimum when he is at home, there is the occasional four-latter word in the Green Day show.
"I didn't know if I would ever get an opportunity like this again so I wanted them to see it. Yeah, it's a bit confronting in spots but we did warn them," he says.
"They thought it was the best thing ever and I think it encouraged them to get more into musicals at school this year.
"And I don't think I swear that often."
But as St Jimmy, Jamieson plays American Idiot's "sex, drugs and rock'n'roll" character. He knows what you are thinking about that and he appreciates he has certain experience at playing the provocateur. His character's role is to entice the directionless Johnny into a downward spiral before he decides to clean up his act.
"Well, yes, St Jimmy does embrace the hedonistic lifestyle and encourages Johnny to do so," Jamieson says.
"Whether I had to do a lot of character research for the role, I will let you be the judge of that."
Jamieson suggests Silverchair's fourth album Diorama, released in 2002, could be perfect for a similar treatment.
"That album has really great wide-screen, musical theatre-style material which could translate," he says.
'Even the name of it sounds like a stage show."
Green Day's American Idiot runs at Brisbane's QPAC Playhouse Theatre on April 13 to 21. Tickets on sale from October 9.
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