The 21-year-old American model dedicated a sweet post to the English singer on Instagram in honor of the occasion.
"Happy birthday my handsome! so lucky to know and love a soul like yours," she captioned a photo of her beau. "wishing you the best year ever!!!
Hadid and Malik were first linked in November 2015 and made their red carpet debut as a couple at the Met gala in May. The singer said in the September issue of Elle U.K. that he and Hadid complement each other well.
"She's super intelligent," he gushed of the model. "I think that's why it works so well. And we do the same type of job so we get that with each other."
Malik spent the Christmas holidays with Hadid and her family -- mom Yolanda, sister Bella and brother Anwar -- in Aspen, Colo. He appeared in a series of Instax photos that Anwar posted Dec. 25 on Instagram.
"Happiness is seeing your kids happy and realizing they turned out to be really good and genuine people," Yolanda said the couple's relationship in September.
Hadid is known for her modeling work with Guess, Victoria's Secret and Chanel. Malik, meanwhile, came to fame with the boy band One Direction, and has since released the solo album Mine of Mine.
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