They've coped with the months of rehearsal, the old-fashioned costumes, the uncomfortable microphones and the long hours devoted to learning lines, lyrics and dances while maintaining their enthusiasm and energy. And, all of them talk up the show like pros while maintaining the spontaneity and appeal of unspoiled children – there don't appear to be any annoyingly precocious showbiz brats here.

Georgia Forster, 12, and Callum Doherty, 11, are one set of Banks children and Victoria Hunt and Jake Keen, both 10, are the other.

Georgia says, "I did my first show when I was nine – Fiddler on the Roof with Philo. It was fun, a great experience."

Mary Poppins is her fourth show. She had read the PL Travers book and seen the Disney movie and said she loves the stage show too.

"I like the magic, I like how it engages you – it's extraordinary, it puts you on the edge of your seat."

Callum started earlier – his first show was Wonder in Aliceland when he was six – and Mary Poppins is his third time on stage.

"It's a great show. The magic is really good. The old songs that were in the movie really appeal and the new songs added in are really clever."

This is Victoria's first musical production. She knew the movie and says, "I like singing and when my parents told me about the show I thought 'Why not give it a go?'"

Both of the girls say one of the highlights of the show for them is the number Playing the Game in which the children's toys come to life – and so does Callum.

Jake particularly enjoys the number A Spoonful of Sugar in which there are some magical moments including a cake instantly rising. His first show was Annie Get Your Gun, when he was eight but Mary Poppins is, he says, "a once-in-a-lifetime experience".

"It's just amazing to be on the stage in the costumes. Everyone knew it, they all knew the story, and I got to be part of that."

Jake and Callum attend the same primary school but didn't know the girls who also hadn't met each other but all say they have become friends and there's no jealousy involved – though there is the occasional moment of good-natured teasing.

The children have enjoyed working with the adult cast and crew, and it seems the feeling is mutual. Director Stephen Colyer says, "Both sets of children are so perfect, so focused" and both Alinta Chidzey, who plays Mary, and Shaun Rennie, who plays Bert, also praise them.

Rennie says, "They're really delightful, really good" and Chidzey says, "I love them – it makes me want to have kids now!"

Mary Poppins is on at the Canberra Theatre until March 29. Bookings: canberratheatrecentre.com.au.