Grande posted a photo of Miller on her Instagram page Saturday afternoon without a caption.
The black and white picture showed Miller sitting on the ground while looking up at the camera.
The 26-year-old rapper and producer died Friday after being found unresponsive in his Los Angeles home. An autopsy is pending to determine the exact cause of death.
Grande and Miller dated for two years before breaking up in May. Grande spoke publicly about their toxic relationship and Miller's substance abuse.
Many people are blaming Grande for Miller's death. Since then, the singer has disabled her comment section on her Instagram, and sources close to her says she is devastated.
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