And is a heavy metal guitar virtuoso who now has fans across the nation after winning over the judges on Australia's Got Talent.

The north Canberra boy would normally be in year five but his exceptional intelligence has seen him fast-tracked to year seven this month.

He is now dealing with making the semi-finals of Channel Nine's top-rating talent show after he performed a rendition of Crazy Train by Ozzy Osbourne.

He performed the song it in front of judges including Kelly Osbourne, whose father is heavy metal legend and lead singer of Black Sabbath Ozzy Osbourne.

All four judges gave him a standing ovation after his blistering performance and all put him through to the semi-finals, expected to be televised in march.

Kelly Osbourne told Callum if he kept playing the guitar he could be up there with Ozzy's bandmate Randy Rhoads who also wrote the song.

"Your guitar playing is exceptional. I don't think people realise how difficult that was. You blew me away," she said.

Kelly told an astounded Callum that her father would "100 per cent" see his performances and later confirmed that Ozzy had indeed witnessed the 10-year-old's guitar-playing and "he was in shock and he couldn't believe it".

Callum told us this week it was "a bit nerve-racking".

"I was not expecting to go so well," he said.

So surely Ozzy will be flown over to play with Callum? Now, that would be great TV.

"Fingers crossed," said his dad, Doug McPhie.

Callum started playing guitar when he was four.

His dad acts as his roadie when he busks around Canberra, usually in Garema Place, near the Canberra Centre and at the Old Bus Depot Markets. He's also performed at The Basement in Belconnen, as long as it's not too late at night.

"People kept saying to us he should go on Australia's Got Talent. It's the only show he could go on because he's so young. I think you have to be 14 to go on shows like The Voice," Mr McPhie said.

His mum, Melissa Freeman, said they were very proud of Callum.

"We're really excited about it," she said.

Callum is a member of Mensa, which accepts members whose IQ is in the top 2 per cent of the population, and he has received $2000 from the organisation for his studies.

"My dream job would be to be a musician and an astrophysicist like Brian May from Queen," he said.

Other than that, he is just like any other kid.

"I like playing pinball and go-karting and taekwondo and obviously watching television as every other 10-year-old child in Australia does," he said.

Callum puts all the money he makes from busking back into his musical equipment. He says that support from Canberra has been critical to him getting so far in music and he hopes those in the national capital continue to back him while he is on Australia's got Talent.

"In a word Canberra - 'Thanks'," he said.