On Thursday, the couple shared the news on social media, revealing that they had welcomed their daughter over the weekend.
Alongside a close-up image showing Malik comforting the newborn, Hadid wrote: “Our girl joined us earth-side this weekend and she’s already changed our world. So in love.”
Meanwhile, the former One Direction singer shared a photo of the baby’s hand clutching onto his finger, writing: “Our baby girl is here, healthy and beautiful. To try put into words how I am feeling right now would be an impossible task.
“The love I feel for this tiny human is beyond my understanding. Grateful to know her, proud to call her mine, and thankful for the life we will have together x.”
The couple are yet to announce the baby’s name.
A number of Hadid and Malik’s celebrity friends congratulated them on the news in the comments section.
Model Hailey Bieber wrote: “Welcome babygirl! So happy for you guys” and Kourtney Kardashian shared a series of heart emojis.
Actor Emily Ratajkowski also commented: “Congratulations Gigi & Zayn!!”, while model Olivia Culpo added: “Ahhhh!!!!! HUGE congrats!!!!! I can’t wait to meet this angel.”
Speculation about the pregnancy began in April when TMZ claimed that family sources had confirmed the couple, who have been dating on and off since late 2015, were expecting their first child together.
Three days later, Hadid confirmed the news during an appearance on The Tonight Show starring Jimmy Fallon.
After Fallon congratulated her on the pregnancy, she replied: “We’re very excited and happy and grateful for everyone’s well wishes and support.”
Shortly after announcing the pregnancy, Hadid revealed that she had been pregnant during fashion month earlier in the year, in which she had walked in shows for several designers.
Speaking on an Instagram Live, she said: “People think I do fillers on my face, and that’s why my face is round — I’ve had this since I was born. Especially Fashion Month, when I was already, like, a few months preggo, you know.”
The couple have kept the pregnancy fairly private, with the model showing her baby bump for the first time in July, just two months before her due date.
In one photo, Hadid was pictured wearing a flowing white gown, as she knelt on the floor and cradled her stomach. She captioned the post: “Growin an angel [sic].”
In another image, the 25-year-old shared two portraits in which she could be seen showing her profile in a sheer, chiffon mini-dress. “7.26.20,” the model wrote.