Mel Staples describes her one in a million find as 'the weirdest thing.'

When Mel Staples asked her eight-year-old son to pick apples from a tree on their property she was baffled at the small harvest he returned with.

"I picked up one and it was a like a granny smith apple and a red delicious apple had both been cut in half and then joined together.

"It was just this perfect line right through the middle of the apple and it was just the weirdest thing," says Ms Staples.

The apple was grown on Ms Staples' property in Kingston, southern Tasmania, and after posting the photo to social media she says her friends simply couldn't believe it.

"They thought that I'd been having them all on and painted this apple and put it on Facebook as a joke," she says.

Former specialist apple grower Bob Magnus says until now he'd never seen an apple like the one found by Ms Staples.

"One like hers is very rare but there's plenty of mutations happening in apples all the time," he says.

The former apple guru explains that 'apples mutate very readily' and the original gala apple would be almost unrecognisable from the ones today because of the mutation that has occurred.

"Someone selected a red mutation here or another mutation there and the one that you see pretty much every day in the shops is royal red gala.

"That has a propensity to try and revert back to be the old gala because of the genetic instability and that is how these genetic mutation occur," he says.

Half red and half green apples are rare, but not unheard of. A fruit grower in the UK found a golden delicious in 2009 that was split in colour just like Ms Staples' apple.

Mel Staples and Bob Magnus spoke to Ryk Goddard on ABC 936 Breakfast