NME reports Grande posted the same message to her Twitter but later deleted it.
Miller and the '7 Rings' singer dated for two years before calling it quits in May of last year. The rapper tragically passed away on September 7 following a drug overdose at his home in California.
Following his death, Grande posted an emotional tribute that read: "I adored you from the day i met you when i was nineteen and I always will. I can't believe you aren't here anymore.
"I really can't wrap my head around it. We talked about this. So many times. I'm so mad, I'm so sad I don't know what to do."
"You were my dearest friend. For so long. Above anything else. I'm so sorry I couldn't fix or take your pain away. I really wanted to. The kindest, sweetest soul with demons he never deserved. I hope you're okay now. Rest."