The Smash star admits she and her husband, musician Brian Gallagher, were always on the same page when it came to having kids, because they had long accepted that their chosen career paths left little room for a family.

However, Megan is glad they have been able to find time for both, because she now cannot imagine life without her first child, two-year-old daughter Viola.

"To be honest, separately, neither Brian nor I ever thought we were going to have children," she told Fit Pregnancy and Baby magazine. "I had this idea from childhood that there wasn't room for parenting and my career, and I chose my career. Thankfully, I was totally wrong."

The 35-year-old is expecting a little brother for Viola in March (17), and she is enjoying everything about her pregnancy the second time around.

"I didn't have morning sickness either time - knock on wood," she explained. "Before I had (Viola), I thought it was going to be weird to feel a baby moving in my belly. But I love it - even the kicking and punching.

"Near the end of my last pregnancy, my mum said, 'You'll miss her when she's not in your tummy anymore.' She was so right."

And while Megan will likely announce the arrival of her son when he is born, fans shouldn't expect to see many photos of her boy on social media.

"I don't post many photos of my daughter on social (media)," she admitted. "I don't judge other people for it, but I feel they're her images to choose what to do with. I'll e-mail pictures to family, which forces me to engage with them instead of hoping they like my post."