Baby on board!
"35 years ago right around now I was born in sunny Adelaide," the Hacksaw Ridge star began her Instagram caption on Friday, Feb. 26. "Today I am thinking of my mothers transition to motherhood and feel grateful to her for all she has done for me."
"I celebrate her, a healthy full life & the miracle of birth," she continued. "Reflecting on this surrounded by my darling babies, including our newest little love."
Teresa cheekily added the hashtags, "we have so many children" and "the best kind of birthday present."
The star's famous friends gushed over the couple's baby news. Rumer Willis commented, "Happy Birthday Beautiful and congratulations."
"Happy Birthday!! So excited for you guys," Claire Holt replied with Michelle Monaghan adding, "Goodness gracious!!!! Congrats on your beautiful, growing brood!"
While the Australian star actress announced her pregnancy, she didn't share too many details about her little one. This will be her and Mark's fourth child together, as they're already parents to Bodhi Rain, 7, Forest Sage, 4, and Poet Lake, 1.
Mark is also a dad to his son Isaac from a previous relationship.
Teresa has been open and honest about her motherhood journey. Last summer, the actress explained how becoming a parent "liberated" her after she shared she suffered from the eating disorder orthorexia. According to the National Eating Disorder Association, the disorder is described as "an obsession with proper or 'healthful' eating."
"My body just blossomed and I had this big belly and I could feel life within me, and it was just incredible seeing what my body could do," she said about her pregnancy on the Me After You podcast. "I was getting stretch marks on my boobs and cellulite all over my bum and the backs of my thighs."
"I was finally liberated from these judgments that I had surrounding my body, which I realized had existed since I was ... a teenager," she continued. "Since being a mom, I've embraced it all. The lumps and the bumps and the stretch marks... it's a map of my journey of bringing my babies into the world."