Speaking to WHO in August, the then-pregnant star spoke about the family's excitement at preparing for a baby girl.
"I’m like, 'I can do her hair. Oh my God!' All of my hairdressing skills would have been wasted if I had a boy,” she laughed of finding out the gender.
And little Sonny was gearing up for the new arrival, too.
“He talks about the baby, and he’ll say ‘have to be gentle’, and I’ll say ‘yes, we have to be gentle with Mummy’s tummy,'" she shared.
"He has been asking for an older sister, and I’m like, ‘You’re getting a younger sister’. But no, he gets it and he’s excited, which is good!”
Turning 40 on October 27, the Australian beauty currently lives in New Zealand with her little family – and while she's happy getting to know her newest family member, she's definitely still keen to get back on the screen!
"My agent said, ‘Come back now … This is the last kid right? We’ll do a job in between if you’re going to have another one,'" she told WHO.
"But no, I think this will be the last kid and then [I’ll] get back on the screen."
Melanie was also named as the local face for L’Oréal Paris Elvive last December, representing the multinational haircare brand’s Extraordinary Oil collection.
On the partnership, Senior Brand Manager Emma Graham from L’Oréal said, "Melanie perfectly embodies the L’Oréal Paris brand ethos. She is a strong, confident woman who empowers others around her, making her the perfect person to represent the Elvive brand, and we are thrilled to have her join the L’Oréal Paris family."