Kushner shared the good news on Sunday, March 14, on Instagram. "Welcome to the world," the 35-year-old captioned the sweet pic of their baby taking a nap in a blue hat.
Kloss herself has yet to post about the new arrival on her own social media, but fans and friends took to the Kushner’s comments to wish the new parents well.
"Congrats !!! Enjoy every moment. They grow so fast !" Gisele Bündchen wrote.
"Congratulations!!! It’s life’s greatest gift," one fan gushed.
"Mazel tov and welcome to the world," another user wrote.
Kushner did not reveal the baby’s name or sex in the announcement post.
The news that Kloss was pregnant broke in October before she confirmed that she was expecting on her Instagram a month later. "Karlie is overjoyed to be expecting her first child in 2021," a source told PEOPLE at the time. "She will be the most amazing mother."
Kloss and Kushner tied the knot in 2018 and threw another lavish wedding ceremony a year; they began dating in 2012. While the two seem very much in love, the supermodel has been candid about how she feels about her husband’s side of the family.
The 28-year-old "really followed my heart on choosing to be with the person that I love, despite any complications that came with it. You know, I knew for me, it was worth it to fight for that," she said, according to InCharge with DVF. Her husband’s older brother is Ivanka Trump’s husband, Jared Kushner.
"I think that in my career too, you know, being true to my heart or being true to myself, when I know that something is not aligned with who I am, and the message I want to send to the world, or the kind of person that I want to be maybe that comes back to character. But like, my heart often is telling me exactly what I need to hear."
Kloss also famously stepped down as a Victoria’s Secret angel and instead decided that she was "stepping into [her] power as a feminist."