The 25-year-old model - who revealed in April that she is pregnant with her first child - shared a new snap of her and Zayn, 27, kissing and captioned it ''baby daddy''.
And Gigi's famous friends were quick to weigh in, with Hailey Bieber sharing a number of heart emojis, Adriana Lima writing ''Blessings to your new family my dear'', and 'Queer Eye's Antoni Porowski adding the comment ''bébés''.
Zayn's sister Waliyha commented ''I love it'' and ''cutest pic'' and posted a number of heart emojis.
Gigi first confirmed her pregnancy in April, after ''family sources'' first revealed the news.
She said at the time: ''Obviously, we wished we could have announced it on our own terms but we're very excited and happy and grateful for everyone's well wishes and support. Especially during this time, it's a nice silver lining to be able to be home and be together and really experience it day by day.''
And she revealed she has been reluctant to share information about her pregnancy on social media, because she feels there is too much going on in the world - such as the Covid-19 pandemic and the Black Lives Matter movement.
Speaking on an Instagram Live, she said: ''Obviously, I think a lot of people are confused why I'm not sharing more, but like, I'm pregnant through a pandemic. My pregnancy is not the most important thing going on in the world. That's a reason that I felt that it's not really something that I need to share, apart from with my family and friends.
''Obviously a lot of people have lost lives due to coronavirus that was in the beginning of quarantine and is still happening. And then we moved obviously into the reemergence of the Black Lives Matter movement, and I thought that our presence on social media should be used for that.''
We spoke to The Corrs' frontwoman about her festive new release.
We want to speak to the Grammys manager...
From child star to rockstar, Taylor Momsen has been through quite the career evolution in her time - and all by the age of 27!
True stories of music and the macabre...
Doja Cat isn't the only one who shocked the world with a new image.
Eight stunning covers of Nine Inch Nails as we welcome them into the Rock and Roll Hall of Fame.