The Figtree 10-year-old was selected from a field of more than 100 girls for the child role of Young Eponine in the Cameron Mackintosh production, which hits Sydney's Capitol Theatre in March.

Mikayla, who only recently started singing lessons, sang Castle On A Cloud for her audition in Sydney.

"It was my first big audition," said the Lindsay Park Public School year 4 student.

"I was very nervous at first and I had to sing a song by myself.

"It turned out to be really fun and a good experience."

Despite only having had a few lessons at Voiceworx School of Performing Arts at Coniston, Mikayla stood out during the two days of testing for the part.

Mikayla's mother Mylie Okely, a dance teacher who runs the Sydney-based Goodhew Academy of Dance with her two sisters, said her daughter had a quiet confidence about her.

"She loves to give things a try and she is very determined," Mrs Okely said. "I think she really loves being on stage as well."

Mikayla, who dances at Kazzajazz Modern Dance Studio in Wollongong, has had plenty of stage experience as a dancer, through taking part in end-of-year concerts and eisteddfods.

Dancing since she was a toddler, Mikayla is an all-rounder who enjoys hip-hop, jazz, tap, ballet, modern and contemporary, and acrobatics.

Mikayla will head to Melbourne next month for 10 days of rehearsals before flying to Perth after Christmas for the Western Australian leg of the show's national tour.

She will be accompanied by her mother and father, Professor Tony Okely, director of the University of Wollongong's Early Start Research Institute.

The parents will take turns in Perth, with one staying in Wollongong to look after Mikayla's brothers Sam, 14, and Max, 12.

"We are very excited for Mikayla," Mr Okely said. "It's a once-in-a-lifetime opportunity."

Mikayla is one of four girls who will share the role of Young Eponine. She will also perform in the show's ensemble. After Perth, Mikayla will be on stage for the musical's Sydney run from March to October.