Taking to Instagram, the model made the happy announcement with a little help from her 19-month-old daughter Luna.
In the video, Teigen asks her little girl, "Luna, what's in here?" To which the gorgeous tot responds, "Baby!"
The 31-year-old confirmed the news by cheekily captioning the footage: "It's John's!"
In February 2016, Teigen opened up about her conception struggles, confirming the couple chose to implant a female embryo during the in vitro fertilization round that resulted in the pregnancy with their daughter.
“The first little girl didn’t work, and then the second is Luna,” she told InStyle, explaining that she and Legend started with 20 embryos, but that number was narrowed down to three after screening and based on what was “going to be good for [my] body.”
The soulful singer, 38, and his wife have been married since 2013.