The couple made the announcement over the holiday weekend, posting adorable matching Instagram images on New Year's Eve. In the sweet snap, Ferrera is making a kissy face and holding up a onesie emblazoned with the phrase "Mas besos," which means "More kisses" in Spanish.
"We're welcoming one more face to kiss in 2018!" Ferrera captioned her photo, adding, "Wishing you #MásBesos in the New Year!"
Williams shared the same image on his own Instagram page, writing, "Making room for new and beautiful things to come in 2018!"
This will be the first child for the pair, who have been married since 2011, and a couple for 12 years.
Ferrera has plenty of practice around babies thanks to her continuing close relationships with her "Sisterhood" costars Blake Lively,Alexis Bledel, and Amber Tamblyn, who all became mothers themselves in recent years. We love the idea of a third flick -- rumored to be in the works, but not confirmed just yet -- that focuses on the characters as moms, too. Here's hoping Ferrera's impending bundle of joy offers plenty of potential inspiration for her onscreen alter ego (and inspires filmmakers to greenlight the project).