Bella Thorne gave boyfriend Mod Sun's fans a treat on Friday, March 9, as she came out onstage to perform a track with him during a concert in Minneapolis.

FilmMagic

The "You Get Me" star danced and gesticulated as she performed a song they co-wrote together called "B---- I'm Bella Thorne" and then packed on the PDA, according to TMZ.

Show-goers told TMZ that Bella watched most of the concert at the Music Hall Minneapolis from the side of the stage, however near the middle of Mod's set, out came Bella for the collaboration, which is her song but was produced by Mod.

These duets seem to have become something of a regular occurrence for the singer-actress, 20, and the rapper, 31, as Bella also joined him last month at a show in West Hollywood.

March 10 is Mod's 31st birthday, which makes Bella's surprise appearance and the heavy public displays of affection on stage in the Twin Cities the night before all the more rock 'n' roll.

Bella took to Instagram to wish her musician boyfriend a happy birthday in the caption of a photo of him on stage.

"Every day is a celebration of you because your soul is so beautiful. Happy birthday modsun," she wrote.