Fast forward a few years and the now 26-year-olds are starring on season three of the family-favourite show, LEGO Masters Australia.

"From the first time the roller doors went up, it was pretty surreal- "This is really happening'," Michael, who is a physiotherapist, now working at KPMG, said.

The pair, who filmed the show in Melbourne last summer, have proved to be contenders for the $100,000 prize, winning the Hero's Quest Challenge, coming up with a giant Temple of the Tiger.

They broke the winning streak of Gus and David while earning kudos from judge, The Brickman aka Ryan McNaught.

"He is terrifying," Harrison said of the LEGO legend.

"He's a lovely person, a very nice man. But in terms of LEGO, he's so far up there. We were like, 'Please, just be happy with what we've done'."

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Michael, from Jerrabomberra, in Queanbeyan in NSW's Southern Tablelands, said they wanted to make The Brickman proud, just like a parent.

"He has the amazing ability to stress you out with a single look," he said, with a laugh.

Harrison, from O'Connor, in Canberra, is finishing his doctorate in chemistry while also a teaching fellow at the Australian National University.

He got his first set of LEGO when he was four or five.

"I got it for Christmas and straight away smashed it out, much to my parents' disappointment it didn't take longer to do," he said, with a laugh.

Michael said he liked building LEGO as an adult because it was a great stress release.

"If you screw it up, you can start again," he said.

The pair confirmed they do get breaks during their epic builds on the show, but they say they are so in the zone, the hours fly by.

"It'd be like, 'three hours have gone by and I forget to drink some water'," Harrison said.

Harrison said he and Michael worked so well as a team on the show because they knew and trusted each other so well.

"We can be really honest with each other and know it's not coming from a bad place. We're both very competitive and we just wanted to submit something good," he said.

"Michael's definitely the stronger builder of the two of us. He has a pretty wild imagination. Being a bit of a logical person, it's my job to solve the problems and bring Michael's ideas to reality."

Michael said being able to have a laugh also helped, making often humorous rather than artful pieces.

They are living the dream.

"It's really nice to be in a room where you have every single brick you need and someone cleans up after you," Michael said.

(And Canberrans can check out some of The Brickman's work here in the national capital - he used more than 150,000 to build a humorous version of Parliament House, which is on permanent display at the real Parliament House.)