The 25-year-old supermodel revealed the exciting news to Jimmy Fallon while making an appearance on "The Tonight Show" on Thursday.
"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,” Hadid said.
She continued: “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.”
The star also revealed her current craving: everything bagels. "I eat an everything bagel a day," she said.
Hadid recently celebrated her 25th birthday with Malik, 27, and her family, including sister and fellow supermodel Bella Hadid.
She shared several photos on Instagram from the festivities, which included large “2” and “5” silver balloons, as well as a cake, which, of course, was shaped like a bagel from “Cake Boss” star Buddy Valastro.
“Had the sweetest day celebrating my 25th birthday with my quarantine family, who made it so special for me, along with all the love I felt from all over the world!” she captioned the post.
Gigi told Fallon she was overwhelmed by Buddy's special birthday cake surprise.
“I don’t know if it was my hormones right now or just like quarantine emotional-ness, I cried every five minutes for an hour every time I thought about how Buddy made my cake,” she said.
Fox News' Mariah Haas contributed to this report