St Michael's College in Brisbane School Band and Choir final

STUDENTS from St Michael's College are gearing up for what might just be the performance of their lives on ABC Radio, but first they have a musical showcase and an eisteddfod to get out of the way.

The 60-child St Michael's choir is one of three finalists in 612 ABC Brisbane's school band and choir competition.

The kids have not sung their song of choice, Sarah McLachlan's Ordinary Miracle, since April.

They compete in the eisteddfod on October 25 and the ABC performance is October 27, leaving just one school day for practice.

But the school's music director, Rowan Foster, said she hoped the lack of preparation would not be a problem.

"The kids are really good, they pull things together very quickly," she said.

"They knew it well when we first did it so I'm hoping I can reinvent it and knock a bit of life back into it.

"Often when the children have had a long break in not singing a song they put new life and energy into it."

The song starts slowly with soft piano and a spine-chilling vocal solo from 12-year-old Lexi Waddel-Bajor.

Ms Foster said the children had a special ability to engage with the lyrics and convey the song's inspiring message.

The choir competition caps off a big year for the school, which won the national Earn and Learn competition, took out two sections at the Queensland Youth Music Awards eisteddfod and picked up two firsts and a second at the Sunshine Coast Eisteddfod.

The final sing-off will take place on Saturday, October 27. It will be aired as part of a one-hour special hosted by Spencer Howson on 612 ABC Brisbane the following week.

Listen to the choir's uplifting performance in the first round here.

The performance will air from 4pm Sunday October 28 on 612 ABC Digital, online and on ABC smartphone apps.