Many MAFS alum shared their messages of congratulations in the comments.
"Wow wow wow. Biggest congratulations to you and your family . Welcome to the nana club," penned season five bride Melissa Walsh.
Season five's Tracey Jewel also remarked: "Awww beautiful."
Meanwhile Mishel's season seven co-star Hayley Vernon wrote: "Oh congrats hun."
Back when she was on the show, Mishel remarked that since she, her son Sam, 21, and daughter Eva, 19, are so close, they often hang out together.
"Quite often I'll go out with my children and their friends but I end up paying for drinks," the mum-of-two admitted on the show.
Mishel was married to her kids' father for almost 13 years, but the marriage broke down after he cheated on Mishel.
WATCH BELOW: MAFS' Mishel Karen says she's been cheated on seven times. Post continues after video...
In the experiment, Mishel was matched with Steve Burley whom she famously slammed during the final vows, explaining that he strung her along for the experiment and that he made her lose confidence in herself.
"During this experiment my growth was not from your words, and by you had a lot to say. What made me stronger was your rejection. I have felt the least attractive, least sensual I've ever felt in my whole life spending the time with you, and listening to you remind me that you have no attraction," she declared at the time.
"As I always say, a person comes into your life for a reason or a season and Steve, our season together is over. We are done. Steve you have wasted my time."