Gwen Stefani & P!nk Pucker Up at the 2012 iHeartRadio Music Festival

Making for quite the sight to be seen, No Doubt opened up the 2012 iHeartRadio Music Festival with a bang on Friday night (September 21).

During the course of their MGM Grand Garden Arena set, Gwen Stefani and co. were joined by a mohawk-rocking P!nk for a rendition of the classic hit "I'm Just a Girl."

With P!nk doing some push-ups on the stage before delving into the lyrics, she later dove in for a steamy girl-on-girl smooch with Miss Stefani.

Following No Doubt at this year's iHeartRadio Music Festival opening day were acts including Miranda Lambert, Usher, Green Day and Rihanna.

Enjoy the pictures of Gwen with her No Doubt bandmates and P!nk at the 2012 iHeartRadio Music Festival (September 21).