"Today's gig might be the best one I've ever gotten.. finished product coming soon! #bucketlist" Matt captioned a photo from the Playschool set.
Matt couldn't wipe the grin off his face as he posed with beloved toy Jemima behind the scenes.
The former reality star, who shares two daughters with fiancee Laura Byrne, then shared a series of videos from inside his changing room.
"This is my changeroom for this morning. I'm going to be lame, I can't tell you what I'm filming but I will say its something I've wanted to do for a very long time. It's very sick," he told the camera.
Matt then hilariously filmed himself chatting to Jemima - an iconic toy regularly featured in the series.
"I just want to say that I've worked with a lot of professionals in the industry and I honestly thought you were one of the best. You did such a good job today," he told the rag doll.
Matt's exciting announcement instantly sent fans and fellow celebs into a frenzy.
"OMG is that Jemima!!!!!! dduuuuuddddeeeee," former Married at First Sight star Johnny Balbuziente commented.
While Matt didn't explicitly say his new gig was on the classic kids' TV show, ABC all but confirmed the casting decision by commenting: "Iconic duo."
This story originally appeared on our sister site, Now To Love.