Chrissy Teigen tweeted Wednesday night: "Somebody's herrrrrrre!" with the baby bottle emoji.
Her husband, John Legend retweeted the post.
The couple have a two-year-old daughter, Luna Simone Stephens.
CNN has reached out to Teigan's representatives for comment.
In November, Teigen enlisted Luna's help with the announcement on Instagram.
"Luna, what's in here," Teigen asked her daughter.
"Baby," Luna said, uncovering her mom's baby bump.
Teigen discussed her past struggle with infertility in 2015 on her now canceled daytime talk show, FABLife.
"We would have had kids five, six years ago if it happened," Teigen said. "It's been a process." We've seen fertility doctors."