The 32-year-old model shared a cute picture of Legend and 21-month-old Luna with her 9.6 million Twitter followers Sunday.
The snapshot shows Legend holding Luna with his head directly over the toddler's. Dad and daughter both show smiles as they pose for the camera.
"Look at these twin humans," Teigen captioned the photo, which received over 247,000 likes.
Look at these twin humans pic.twitter.com/TX5xto0Gh2— christine teigen (@chrissyteigen) January 21, 2018
Teigen and Legend welcomed Luna in April 2016, and announced in November that they're expecting their second child. The model posted a new photo of her baby bump Saturday that was taken during a recent girls trip.
"Girls weekend - Quaker Hill, NY - 2018," she wrote.
Teigen's caption led fans to speculate the star is expecting another daughter. She said in an interview with E! News last week that Legend asked her to keep their second child's sex a secret.
"We knew when we put [the embryo] in but John was like, 'Make sure you don't say it. Let's have one thing for us,'" the model, who is expecting via in vitro fertilization, said.
"Of course I'm probably going to end up saying it but I'm just going to do this favor to him for as long as I can," she added.