Friends and fans have flooded the post with messages of well-wishes, including Steph Claire Smith.
Elyse and Josh, who won the 2017 season of The Block, first announced their second pregnancy in January this year.
“Very, very grateful for baby number 2,” Elyse wrote alongside a gallery of cute family snaps on Instagram.
“Half way until Sunny is a big brother.”
Many of the couple's friends flooded the comments with congratulatory messages, including Anna Heinrich, Steph Claire Smith, Ash Barty and Bec Judd.
The 29-year-old model gave birth to Sunny Barker in February 2021, revealing to WHO that motherhood was “the best.”
"I'm adoring it!” She explained. “I feel like I say this all the time, but things get better and better every day."
“It’s been new, unpredictable, wholesome. I am loving the role of Mum, and grateful to be where I am with my beautiful family,” Elyse told WHO, shortly after her son’s birth.
"Sunny is growing into such a little dude now. He's so alert and fun, he's loving, full of smiles and he is so cuddly. I could smooch him all day long.”
“Josh and I often look at photos of him in bed. Almost every night the two of us look at each other thinking, "should we get him up for a quick cuddle?" It's tempting!"