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Gwen Stefani and husband Gavin Rossdale shared a romantic kiss during a surprise joint performance at the 23rd annual Almost Acoustic Christmas at Gibson Amphitheatre in Los Angeles Sunday, Dec. 9.

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The No Doubt singer, 43, and Bush rocker, 47, met and fell in love at the same event 17 years ago when their respective bands were on tour. The husband and wife of ten years (parents to Kingston, 6, and Zuma, 4) performed Bush's hit, "Glycerine" together.

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Who suggested teaming up for the romantic duet?

Rossdale told Rolling Stone that his wife came up with the idea -- much to his surprise.

"I thought it would be so powerful, the two of us on stage like that, that's what we went for," he said. "This is the culmination of two years of work, and then to finish it off playing here, in this venue, this full circle thing, it was an incredible night."

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And during Stefani's set with her No Doubt bandmates, a source tells Us Weekly that Rossdale was being a supportive husband backstage. "He was standing near the sound booth, grooving a little bit and he had a big smile on his face, watching Gwen," the eyewitness tells Us.

This article originally appeared on PICTURE: Gwen Stefani, Gavin Rossdale Kiss on Stage Where They First Met 17 Years Ago