“I always hope that the people that are on the bong get a taste of an opiate at some point,” muses Ben Folds. We’re discussing whether his upcoming show with the Melbourne Symphony Orchestra will work as a gateway drug into classical music. “Nah, I’m just kidding.”

He kids a bit. Folds is probably best known, to Australians at least, for his insolent brand of slacker piano pop. But for the last few years the songwriter has been working with orchestras around the world performing adaptations of his back catalogue and original classical compositions.

Fans of Folds won’t be surprised by the orchestral development. He played in orchestras as a kid (“I’d count measures and hit the triangle every once in a while”) and dropped out of the University of Miami's Frost School of Music. His music has always displayed an anachronistically baroque strain. “As a piano player that moves around the voices a little bit more correctly than a normal pop musician does, that ‘kinda translates to the symphony more easily than some stuff does,” he says.

MSO assistant principal cellist Nick Bochner says that behind Folds’ nonchalant public persona is a consummate professional. “In rehearsals he’ll play by himself, just sat at the piano, very much like how a piano soloist would normally,” he says. “But when he came out to perform he was just amazing. He interacts with the audience, he does spontaneous stuff, he changes songs from night to night. I think he’s just a constant performer, just fantastic.”

For his part, Bochner appreciates the change in tenor that comes with the Folds show. “The atmosphere in the hall, you know I guess orchestral musical is usually a little more formal, people are more quiet,” he says. “Whereas when you play with someone like Ben, you walk out on stage and the roar is absolutely deafening.”

Folds believes the staid atmosphere that often surrounds classical music is somewhat artificial. “People have taken it and run to the high-brow extreme. I think it has thrown up a barrier that didn’t really need to exist,” he says. “But I think the orchestra will always exist, because it’s civilisation, you know? In the moment you see that no longer represented, we’ll be back to caves.”

He’s participating in that long tradition with his Piano Concerto, which will not only be performed at this week’s show, but will soon be widely released as an album. It’s definitely a departure. “Initially, there was a really nasty root canal gone bad, and a lot of prescription drugs and time spent in bed kinda just hallucinating. It started at that moment,” he says. “I’d wake up and have all these crazy motifs going through my head, and I’d go to the piano and pound them out.”

Piano Concerto features some unusual instrumentation. Midway through the performance, the entire orchestra pulls out their mobile phones and triggers the ringtone. “They dig doing it. It’s a bit ridiculous but it sounds beautiful,” he says. “You hear [Folds affects a deep official voice] ‘Please, put away all cellphones’, then seconds later everyone’s whipping their cellphones out. I think that’s funny.”

If it sounds like a gimmick, Folds has a solid rationale. “Really, musical response is just a series of dopamine releases,” he explains. “If you can get a surprise, then you’ve altered the cadence of the way people are reacting to the music. Every time you surprise someone, you get a musical advantage.”

Surprising as his show may be, Folds still isn’t sure whether it’ll introduce a new generation to the MSO. “You’ve got to grow a new audience for any art form. You have to be educated yourself to understand it. That’s the best I can hope to do,” he says. “But there’s no guarantee people are going to show up to, say, Mahler the night after I play.”

Ben Folds is performing live with the MSO Friday December 19 and Saturday December 20, 2014. For more information visit mso.com.au/whats-on/2014/ben-folds.