Watch Pink Join Guns N' Roses Onstage in New York

During the first of their three dates at New York's Madison Square Garden Wednesday night, Guns N' Roses brought out a somewhat unexpected guest for the G N' R Lies song, "Patience."

In what appeared to be an off-the-cuff decision, frontman Axl Rose invited pop star Pink up to the stage to help him out with some of the song's closing lines. Though seemingly caught off guard by the invitation, Pink didn't take long to get in step with the band, and seemed to enjoy singing with Rose, who was all smiles.

Throughout the Not in This Lifetime tour—which brought original members Slash and Duff McKagan back into the fold—Guns N' Roses seem to have revelled in the looser, more spontaneous moments of their lengthy concerts.

At a show in Edmonton in August, for instance, the band took the time to pay tribute to country icon Glenn Campbell—who had passed away a few weeks before—and to the Godfather of Soul, James Brown, with loose but lively covers of "Wichita Lineman" and "I Got You (I Feel Good)."

You can check out this unlikely duet for yourself below.