The 25-year-old model posted unseen pictures from her pregnancy Monday on Instagram.
The photos show a pregnant Hadid posing outside in a formfitting dress. One of the pictures shows Malik, 27, resting his head on Hadid's baby bump.
Hadid and Malik welcomed their first child, a baby girl, in September.
"Our girl joined us earth-side this weekend and she's already changed our world. So in love," Hadid said on Instagram at the time.
"To try to put into words how i am feeling right now would be an impossible task," Malik added on Twitter. "The love i feel for this tiny human is beyond my understanding. Grateful to know her, proud to call her mine, & thankful for the life we will have together."
"Obviously, you know, we wish 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," she said.
Hadid and Malik have had an on-again, off-again relationship since 2015. Hadid is known for her modeling work with Guess and Victoria's Secret, while Malik is a singer and a former member of One Direction.