Calling Miller her "soulmate", the "Side to Side" hitmaker took to Instagram to post an adorable clip.
The clip showed the 23-year-old singer with her beau jamming out to what sounds like a Mexican song in a car while she played around with Snapchat filters.
"Happy birthday to my best friend for life/soulmate @larryfisherman I love you with all my heart," Grande captioned the clip.
The duo has been friends since they worked together on Grande's single "The Way" and its accompanying music video back in 2013.