The 20-year-old shared the heartwarming pic, showing Malik kissing Hadid on the cheek while they laid with her furry pal, to Instagram and wrote in the caption, ":( we love you always chub."
Hadid did not go into the details surrounding her pet's passing, although many fans and followers responded to the pic with support and condolences.
Malik retweeted Hadid's photo, although he didn't share any additional info, and let Hadid's heartfelt memorial speak for itself.
The pic appears to be from early last month when the former One Direction singer dyed his hair light pink. Malik has since shaved his head and trimmed down his scruff.
The cute couple were first linked in November, and have played coy about their relationship. However, Zayn seemingly confirmed they were a couple in the beginning of February while talking with a radio show about Hadid's appearance in the music video for his solo single "Pillowtalk." Check out the video below to hear more.