The actress took to her blog on Tuesday to share the happy news that she's expecting her second child with husband Scott Stuber.
"Scott, Brooks, and I are welcoming a fourth member to our little family—our second child!" she wrote. "I can't even being to explain just how excited we are for a new baby. We are so, so, so blessed as a family, and I'm speechless at the fact that we have the opportunity to bring a second bundle of joy into the world."
"As a new mom to Brooks, an entire world of motherhood opened to me along with a thousand and one questions," she continued. "I absolutely cannot wait to see what life will be like as a mother to a toddler and a newborn, and I really can't wait to see Brooks as an older brother to Baby #2! I just know that he's going to be preciously protective. If it's a girl, he'll be her biggest supporter and confident and if it's a boy, I know they'll be the best of friends, always getting into adventures together."
In the accompanying picture, the 41-year-old beauty is holding up a chalkboard that reveals she's four months pregnant. Meanwhile, Brooks, 2, is proudly sitting behind his own sign.
There was no sign of Molly's growing baby bump on Sunday, as she sported a sheer top (and cat ears) at the Pottery Barn Kids Halloween celebration held at the Mondrian in Los Angeles.
Her son was all smiles as they two stood in front of a pumpkin patch at the event.
We can't wait to see Brooks as a big brother -- congrats to the growing family!