The new bub is the second child of Tracey, who shares a nin-year-old daughter with her ex-husband Jacob Anthonisz.
Tracey announced she and Nathan were expecting the little one back in September last year.
Heading to Instagram, the reality star shared pictures of Nathan and herself, as well as of an ultrasound and an adorable onesie.
“We’re having a baby!" Tracey wrote, "We are so happy to share our beautiful news with everyone.
“I have always believed in second chances and my second baby I’ve been waiting so long for… my daughter Grace is going to be an amazing big sister and I’m so so grateful to be experience pregnancy + motherhood again with my love Nate x”
While Tracey and Nate’s relationship became public in 2019, the pair’s history goes back much further than that.
The expecting parents met some 20 years ago at Churchlands Senior High School. And, yes, they were high school sweethearts.
It wasn’t until 2019 that they long-lost lovers reunited and reignited that young-love flame.
Speaking to WHO at the time, Tracey revealed how she and Nate had finally got the timing right.
“I bumped into Nathan, who was my Year 11 boyfriend,” the 38-year-old started. “The timing was just really bad. We’ve been on Facebook, I guess just keeping tabs on each other’s lives, ever since 2007…
“He Facebook messaged me in early November – because he knows my birthday is in November – and he said ‘how about that coffee?’ and I said ‘sure’. He ended up taking me to a Wildcats (basketball) game, and that was it!”
In February, Tracey and Nathan tied the knot in their hometown of Perth.
"We're married!!!! Mr + Mrs Constable! Forever my always... So this was our big surprise!! A baby shower turned wedding celebration!" Tracey wrote alongside the pic.
The bride continued her caption: "Thank you to our friends and family for making our wedding and baby shower such a special day and the role you play in our lives... thinking of everyone who couldn't make it."
"My husband, thank you for making me the happiest wife, I love you."
Appearing on season five of MAFS, Tracey was paired with creative director Dean Wells and, while the compatibility experts clearly had something right to begin with, their initial physical chemistry soon died out and the couple split right before the experiment ended.
The two have remained friends.