Bieber appeared on stage as fans screamed.
“We thought it might be fun to do something for you guys,” Grande said. “This was not planned at all. Thank you for being here Justin. We love you so much.”
Related: Justin Bieber promises new music after he works on 'deep rooted issues'
Bieber performed his 2015 single “Sorry” and thanked the audience afterward, saying, “I haven’t been on a stage in, like, two years.”
Bieber also teased that he would be back with new music soon, Billboard reported.
“I had to get my groove back, I had to get my swag back, you know what I'm saying? Thank you so much, Coachella, thank you so much, Ariana Grande,” he said. “And by the way -- album coming soon.”
So Bieber's music break may be over sooner than fans thought. After the performance, he tweeted, "That felt right."