They remember getting a call via Skype to tell them they had made the show.

"It was such a shock," Katie said. "You think, like when you win the Lotto, you'd jump up and down and run around the house but we were speechless. It was like, 'What does this mean?'."

What this does mean is that the photogenic couple - she is a newly-qualified midwife; he is an Australian Federal Police officer - have got the golden ticket.

They will have their 1800s cottage in Gundaroo renovated and furnished by the five other teams in the competition.

In return, they travel around Australia renovating the other homes of the other teams. Their journey will be documented on Instagram at @katiealexau

The couple applied for the show last year but had to postpone after finding out they were expecting their first child, Hallie, now 14 months.

"I've always wanted to do a renovation show, it just seems like the best adventure," Katie, 29, said.

"And I just do what I'm told," Alex said, with a laugh.

The couple say they are renovating novices, updating a kitchen at their former home in Melba before moving to Gundaroo to try to replicate their own country upbringings for their children. "It was a lifestyle we wanted for our kids," Katie said.

"The idea of having that responsibility of looking after animals before they go to school, of riding their bikes in the street with other country kids.

"Everyone looks after each other and there's that old-school kind of thing where you can knock on the door of a neighbour and ask for a bunch of basil."

Alex joked their house pre-renovation was "the size of a shed and should not be lived in by humans".

What they both found is that the show's demands were so much more than they expected.

"I told myself I am never going to say, 'We're not going to finish' because I thought that was put on, but the first house, what did I say? 'We're not going to finish'," Alex, 32, laughed.

But they did not find any of the conflict so loved by reality TV shows.

"There's every personality under the sun but for some reason, we all liked each other," Katie said.

The couple met when Katie was running the food delivery business Fudie and Alex was a client. They say they wanted their house renovated so they could "have more babies".

In their renovations, Katie focuses on design while Alex "brings my dreams to life". They both know what they want in their ideal home.

"A place that is homely and welcoming, like it has been there for a long time and is already home," she said.

"It's loved."