The rhythmic gymnast shared the news via her private Instagram account this week, The Daily Mail reports.
'Congratulations on the birth of your son... So proud of you,” one fan wrote in the comments. “Your [sic] going to be an amazing Mum,” another added.
The ribbon-twirler first announced she was pregnant via Instagram in November.
"We are expecting! Our baby is 12 weeks old and it was wiggling his/her arms and legs, I was completely speechless looking at the screen for the very first time," she captioned a photo of her ultrasound. "It was dancing in my belly and it made me tear up!"
Meanwhile, Matty J is still loved-up with The Bachelor winner and Sydney jewellery designer Laura Bryne.
Speaking to WHO earlier this year, the former Bachelor confirmed marriage was on the horizon for the couple.
"We've definitely spoken about it," Matty said. "For us, well, there's no question for me, I've found the person I want to be with long-term, the one I hope to be with forever. But we want to move in together first."
In a jam-packed episode of WHO magazine’s TV podcast, Binge List, we discuss the returns of Arrested Development and The Karate Kid (as spin-off series Cobra Kai). Plus, what’s the verdict on Love Island Australia? We also take a look at hilarious spy thriller Killing Eve, crime docuseries The Staircase and comedian Ali Wong’s Netflix specials. Listen below, or on iTunes: http://po.st/syE3JF or OMNY: http://po.st/28BGXd
This article originally appeared on Marie Claire