Side by side: meet the Shell Cove twins with strikingly similar ATARs

Younger twin Kristian Masi received an ATAR of 97.45 and older twin Michael Masi received an ATAR of 97.20.

"We always get pretty much the same marks and so it was no surprise we've done pretty similarly the entire year," Kristian said.

The Corpus Christi Catholic High School graduates had an extraordinary journey to their HSC exams, both skipping ahead a year of school, and one brother undergoing surgery mere days before the exams.

The 17-year-olds plan to take their acoustic guitars with them to do a gap year busking in Europe.

Studying for the HSC exams was slightly less daunting when they had a best friend to lean on.

With similar interests, the brothers studied the same HSC subjects: English advanced, mathematics extension two, ancient history, music one, and studies of religion.

The pair tested each other on English and ancient history content during their revision.

"It's good to have someone suffering all this stuff with you, so it really makes it feel a lot better once you've finished," Michael said.

While the fraternal twins have lots in common their father Emidio Masi said there's one difference; Kristian is more guarded and considered when responding to new situations while Michael is more spontaneous.

Mr Masi believes the secret to their success is the way they motivate each other.

"When one of them was down and didn't perform well, the other one sort of helped pick them up," Mr Masi said.

"They kept raising each other but not in a toxic way, they never begrudged the other one [for] doing well in an exam, it just meant they would steal themselves to do better next time."

The HSC isn't the first time they've crammed together, the pair skipped ahead a year of school going directly from year seven to nine.

The pair spent their summer holiday learning an entire year's worth of school content.

Once they entered study-mode the pair kept challenging each other.

"We learned like all the different countries in the world and their location and all the digits of pie and stuff like, that wasn't necessary, but we just like testing the limits of our brain[s]," Kristian said.

On the eve of the HSC practical music exam, both brothers were busily rehearsing when Kristian was suddenly rushed to hospital with appendicitis.

"So, I had to have surgery on the day of the exam ... I was very disappointed at first because I put so much effort into it and I wanted to sort of prove myself," Kristian said.

While Kristian spent a week in hospital recovering after his appendix burst, Michael attended the last week of school on his own.

On one of the days the grade had a mufti theme to arrive at school dressed as a dynamic duo or trio.

As a duo himself, Michael took it upon himself to dress up as his "sick brother in hospital".

With a passion for maths, they may study at university after their gap year but for now, their focus is on music.

"I just want to get out in the world and make something," Michael said.