What do a pop singer, an alternative rock band, a jazzy songwriter, an electronic producer and a folk/indie outfit all have in common with an orchestra?

Not that much, seemingly. Yet tomorrow we will all take to the stage with a 12-piece ensemble to perform arrangements of our own songs.

Such crossover endeavours can make even the most open-minded concert-goers think twice. But then, as any seasoned reader of this arts section knows, Music at the Brewhouse is no ordinary orchestra. If anybody can successfully round up such a hotchpotch of styles, it is the group’s artistic director Stephen Deazley: ­conductor, composer, animateur and all-round musical trailblazer.

He has worked ­industriously with us for two months, and the results of these collaborative sessions make up tomorrow night’s Great Rock ’n’ Roll Swindle Showcase in Glasgow. Supported by the Scottish Arts Council, the showcase first broke through two years ago in Perth, where talented local artists had the opportunity to work and perform with Deazley’s collective. In the words of The Herald’s Mary Brennan, the project was a “knock-out success” and was taken to ­Orkney last year, where five more acts were picked to share their music.

This year, the scheme has alighted on Glasgow, with the musicians having been selected from a wide group of applicants earlier this year. “What is evident in the ­Glasgow project is that there is a very clear, very different style for all the five pieces of work,” he says. “They are ­fairly diverse, and that is what we hoped for.” David Knotts, fellow mentor and composer on the project, concurs. “It’s going to be great to see how they all get up and do their own unique thing.”

Also noteworthy is the fact that all the artists are under 25. Many don’t “compose” in a traditional sense, and most have never performed with a classical or jazz ensemble before. Patricia Panther is one such artist: a vivacious, musically fierce singer/­producer, she has savoured the chance to join forces with the more three-dimensional resource of live musicians. “What ­really drew me to the project is that it seemed so open,” she says. “Any genre was ­welcome and there was a chance to be placed in an environment where there is pure, instrumental sound that isn’t electronic. I thought it would be intriguing to see what they could do with my weird sounds.”

Like so much of what is on offer this year, Patricia’s ultra-­modern music may appear to be incompatible with prim strings and nostalgic saxophones. But that hasn’t fazed the two mentors, who have set out to create brand new arrangements and inspire us to think differently about our music. “We’re trying to find a way to broaden horizons, make suggestions and challenge the formula that sneaks into the way all musicians work,” says ­Deazley. “I’m guilty of this, too – you begin to duplicate and replicate what you know best. But what we’re trying to say is: ­“Actually, you don’t have to do this; have a look at that and try something new”.”

Knotts, meanwhile, has been challenging the ­eloquent folk/indie band This Silent Forest to re-imagine the structure, key and time signatures of their songs. “I believe the acts will think differently about how they put their stuff together after the project,” he says. “That’s not something that is entirely measurable but they will definitely think more creatively and imaginatively about their music.”

Graeme Macdonald is the singer-songwriter behind the band. “I’ve been ­learning about music properly,” he says. “My style is very ­simple but David has taught me so much. You can do a huge amount to a song you’ve ­written and push it beyond three basic chords.”

The Brewhouse is an award-winning orchestra and its ­concerts – including The Songbook of Unsingable Songs, which received a five-star review from The Herald earlier this month – are consistently critically acclaimed. Pop musicians are not that used to teaming up with such renowned players, so learning to trust their abilities hasn’t been easy. Deazley recognises this, referring to my own frequently over-zealous instructions in the orchestral score. “You’re writing in all the detail, all the tiny ­little licks that the musicians will naturally do themselves,” he told me. “You learn when not to do that, when to actually use your musicians as a resource and let them help you to do something better.”

One of the performers, the sweet and soulful singer Cheryl Risk, is fitting in those crucial rehearsals with lectures at Strathclyde University, while the youngest band in this year’s line-up, emotive ­rockers Fourth Call, will be back at school the day after the gig. But Deazley insists this is no outreach scheme. “This is really top-drawer stuff,” he says. “We seldom call it an educational project, even though there is a lot of learning going on. We look at it as a major professional opportunity for young musicians.”

Indeed, for all the fruitfulness of Glasgow’s musical scenery, the prospect of collaborating and learning with a five-star ensemble and composer hasn’t been available like this before – and may not be again. Hector MacInnes, chief of the project at Glasgow’s City Halls, describes the Swindle as a once-in-a-­lifetime event, both for the musicians and their audience.

“Even if you’re a very top-flight, big-stage player, you don’t necessarily get to play with 12 or 13 musicians of this calibre on a regular basis,” says Deazley. “To have that opportunity: there’s nothing quite like it in the country. And I’m proud of that.”