The Little Mix singer was seen wearing a giant sparkler on her engagement-ring finger. The couple stuck together on the red carpet Tuesday for the "This Is Us" premiere, and then sat together for the screening.
Fans are adamant that the three-stone ring is an engagement ring, since the two have been dating since 2011, even oceans apart.
Malik said he took four flights in 48 hours to spend time with his rumoured fiancée.
"I'd fly 10 planes to go home and see her," he said. "It's difficult to see your girlfriend 24/7. When you do get to see her, you really make the most of it."
"My mum used to say that absence makes the heart grow fonder, and it definitely does."