The video Grande posted on Friday shows the couple laughing together as he asks her to stop filming him when he is telling a story.
Grande and Miller dated for nearly two years, collaborating on Grande's hit "The Way" and Miller's "My Favorite Part", before breaking up this past May.
Thanks so much for watching, I'm your host Emile Ennis Jr. and I'll see you next time. "I adored you from the day i met you when i was nineteen and i always will", the singer wrote.
Paramedics found Miller, a 26-year-old platinum hip-hop star whose real name was Malcolm McCormick, unresponsive in his Los Angeles home on September 7 and declared him dead soon after.
Cast member Ariana Grande answers questions during the panel for "Hairspray Live!" at the NBC Universal Television Critics Association press tour in Beverly Hills, California, U.S. August 2, 2016.
TMZ's initial (and later revised) breaking-news report about Miller's death irresponsibly implied that Grande was to blame, saying Miller had "had trouble recently with substance abuse ... in the wake of his breakup with Ariana Grande". "I am happy for her and [the fact that she's] moving forward with her life, just as I'm sure she is with me".