The “Gossip Girl” alum shocked fans by debuting her baby bump at the 10th Annual Forbes Power Women’s Summit on Thursday in New York City.
The actress, 35, was all smiles cradling her budding belly in a sparkling gold dress.
She and her “Green Lantern” co-star, 45, tied the knot in September 2012, and the couple started growing their family two years later when James arrived.
Lively, who is already the mother of daughters James, 7, Inez, 5, and Betty, 2, with husband Ryan Reynolds, paired the look with white heels, hoop earrings and a headband.
The “Age of Adaline” star has yet to announce the news via social media.
In fact, one of Lively’s last social media uploads in August showed her flat stomach in a white bikini, although she did not specify when the poolside picture was taken.
Reynolds revealed in October 2021 that he was taking a “sabbatical” from acting to focus on life with their little one
He and Lively have been vocal over the years about their plans for a big brood — even sharing their baby fever before conceiving James.
“If I could spit out a litter of kids, I would,” the “Sisterhood of the Traveling Pants” star told Marie Claire in September 2014.
The previous year, Reynolds explained to Details that he and his wife both came from large families.