Gigi Hadid gives a glimpse into her relationship with Zayn Malik on his birthday

American supermodel Gigi Hadid is going all out on social media on her beau Zayn Malik’s birthday.

As the former One Direction dreamboat rang in his 28th birthday, his ladylove turned to her Instagram and posted a heartfelt tribute for her ‘baby daddy.’

"Team No Sleep!" she wrote. "Happiest birthday to our Zaddy baba. So special. Love you long time, thank you for makin me a mamma to the best girl ever. Wish you the best every single day,” she added.

Alongside the note, she posted an unseen photo with her boyfriend and an illustration of the singer cradling his daughter.

The two have purposely been keeping their relationship strictly private as they have been dating on and off since November 2015.