Christian met Natalie while the pair were studying pharmacy at the University of Sydney in 2008.
"We had tutorials and lectures together and soon became firm friends," Christian said.
"I fell in love with Natalie almost instantly after we started going out a couple of years after sharing the classes. We had similar morals and interests. As soon as we started dating and going for dinner, I knew I wanted to marry her."
However, Christian didn't just want a regular run-of-the-mill-type proposal.
"When you fall in love with someone, I think you want to do something spectacular," he said.
And so, in June 2016, while he was driving through Sydney and caught a glimpse of the Vivid lights festival, he decided he wanted to propose during the fortnight the festival takes place.
"I hadn't put much thought into proposing before, but I knew I wanted fireworks and a private boat. But I also wanted a sentimental approach.
"This was handy because I knew I could use pictures of Natalie I'd amassed over the six years we were dating."
Christian explained that every time he and Natalie went out for dinner in the past six years, he would ask her to make the initial letter of the place with her hands.
"I only did two or three a year to spell out "will you marry me?" so it took a while, but I didn't want her to get suspicious,' he said.
The 28-year-old from Sydney also enlisted the help of a proposal planner, My Proposal Co, to ensure that all of the various elements he wanted involved went to plan.
"I ordered the fireworks and did the planning, but My Proposal Co helped hugely," he said.
"There was a time sheet with music cues, and playlists organised for before, during and after dinner. Nothing was left unplanned."
The A$14,000 proposal panned out by picking up Christian and Natalie on a yacht with a private chef on-board.
The couple then enjoyed a delicious dinner to a playlist, before Mr Zaya presented his girlfriend with four envelopes.
"In the fourth envelope was the 'will you marry me' sign," he recalled.
"As soon as she opened it, Bruno Mars's Marry Me song came on. Everything was timed to perfection."
Christian said the reaction of his now fiancee was 'priceless'.
"She was crying tears of happiness. I had gone above and beyond what she ever expected,' he said.
And of course, she said "yes".
As for the upcoming wedding later this year, Christian said: "Watch this space".
"Three hundred and fifty invites have been sent out, it's going to be good," he added.
