The new mum has also shared details of how her famous dad, Bryan, was in the birthing room when Zan was born.
Sharing a photo of her dad gazing lovingly at his grandson, she wrote: “On the night I went into labour, dad was supposed to drop mum at the hospital (mum was my doola) and then wait in the waiting room.
“But he ended up coming into the room and stayed for the entire birth.”
Matilda is best known for starring alongside her father Bryan in the short film series Lessons from the Grave in 2014. She has also appeared in TV shows Rake and Offspring.
Matilda shares her baby boy with her partner, Scott Gooding, who appeared in My Kitchen Rules in 2013.