Grande, 24, and Miller, 26, decided to end their relationship due to their work schedules becoming too busy but the pair still remain friends, TMZ reported.
Grande and Miller first went public with their relationship in Sept. 2016. They collaborated on songs together including "The Way" and "My Favorite Part."
Miller was by Grande's side following the suicide bombing in Manchester in May 2017 that killed 22 people and injured others during one of Grande's shows in Great Britain. Miller also joined Grande for her One Love Manchester benefit concert that raised money for the victims and their families.
Grande is set to release her fourth studio album titled Sweetener on July 20. The project will include the song "No Tears Left to Cry," her first single since the Manchester bombing.
"Very proud of this girl right here. Welcome back. We missed you. One of a kind," Miller said on Twitter about Grande in April following the release of "No Tears Left to Cry."
very proud of this girl right here ❤️— Mac (@MacMiller) April 20, 2018
Welcome back. We missed you.
One of a kind. https://t.co/aUJC9UL9fb