The model announced the new arrival with a tweet late on Wednesday evening, writing “Somebody’s herrrrrrre” with two baby bottle emojis.
The couple - who married in 2013 - are already parents to two-year-old Luna, who helped reveal their exciting news that they were expecting .
Fans rushed to congratulate Teigen and Legend, with many joking that the name should be either Yanny or Laurel after the star waded in on the audio debate sweeping the world yesterday .
Somebody’s herrrrrrre! 🍼🤗🍼🤗— christine teigen (@chrissyteigen) 17 May 2018
All of Me singer Legend retweeted his wife’s post announcing his son’s arrival.
Standard Online have contacted representatives for Teigen and Legend for further comment.
Teigen, 32, confirmed that the pair were expecting a son at the Grammys earlier this year when she posted a snap of herself captioned “mama and her baby boy”.
Long-time fans of the celebrity couple already knew that baby number two was going to be a boy after the pair revealed this time last year that they had a male embryo left after a round of in vitro fertilisation (IVF).
Teigen and Legend revealed the pregnancy last November, enlisting the help of their daughter to make an adorable clip reveal.
The sweet video shows Teigen and Luna pointing at her mum’s tummy and saying: “Baby”.
Teigen then asks the tot “what’s in there, Luna?” to which she replies: “Baby, baby.”
The star, famous for joking around on social media, captioned the post: “It’s John’s” and later revealed she was due around June 2018.