The former couple -- who called it quits shortly before the "Starboy" artist began dating Selena Gomez -- looked like they were still quite close while hanging out together at a nightclub party at the Cannes Film Festival, on the coast of the French Riviera, on Thursday.
An eyewitness tells ET that the pair was "kissing" at the party, which will certainly continue to spark rumors that their romance is back on!
ET has reached out to reps for both.
The loud, music-filled nightclub meant the pair had to stand very close to talk, and Hadid was seen with her hand over her ex's shoulders several times throughout the night.
Partygoers at the event spotted the high-profile couple excitedly hanging out together, and even greeting one another with a few pecks on the cheek and a close embrace.
Among the numerous photos snapped of the two stars throughout the evening by various people, there is also a pic showing The Weeknd with his arm around the small of Hadid's back, as they talked face to face.
The friendly former flames were later seen laughing together as they looked at each other's phones in the darkness of the club.
It's been 18 months since the runway model and the "Can't Feel My Face" singer parted ways, breaking up in November 2016 after dating for a year and half.
A source told ET at the time that, despite their breakup, the pair were going to remain friends and that there was still "a great deal of love" between them.