Sharing the news in an Instagram post, the mum of one captioned the post: “Mum! I see his doodle!” 😂🙈 Yup, it’s a boy!"
Marni is expecting her second child with her new husband David Robertshaw.
The comedy writer also shares four year-old son Archie with ex husband and former Home & Away star Dan Ewing.
Marni told New Idea that Archie was with them when they found out the sex of their baby.
"Archie was with us when we found out it was a boy - straight away he said: "see mum, I told you I wanted a brother". I think he thinks he controlled the outcome," Marni said.
"It's really exciting. I grew up with three brothers and they are still my greatest friends so I'm really looking forward to seeing Archie form those same bonds. I'm definitely not ready for a three-male house yet, though!
"It's been a while since I did this so we have not exactly baby-proofed just yet. Archie is at a great age for a sibling though, he's extremely helpful and has made a list of all the things he can teach him once he's born."
