Gwen Stefani's band took to the stage for the 2012 iHeartRadio Music Festival at the MGM Grand Garden Arena and during a rendition of the group's anthem, "Just A Girl," the frontwoman told the crowd, "Ladies and gentleman - Pink!"
The "So What" hitmaker then joined in the second verse of the song and sang the rest of the track with Stefani.
After the show, Pink took to her Twitter page to share her experience with fans, writing, "I just got off stage from the raddest surprise performance with No Doubt. She really is that cool. I'm just a girl."