Keith Urban singing "Happy Birthday" to wife Nicole Kidman would have been sufficient, but he super-sized the singalong on Tuesday night (June 19) in Wisconsin.

The "Coming Home" singer selfied a birthday serenade while onstage at Country USA Festival in Oshkosh, Wisc., asking a few thousand fans up front to participate. The best part? They don't call Urban's wife "Nicole" in the song, but rather "baby girl." We're guessing he tipped them off to his nickname for her in advance.

Kidman — whose actual birthday was Wednesday (June 20) — appreciated the gesture.

"What a gift," she writes on Instagram, "My husband and everyone at @officialcusa Oshkosh WI singing me Happy Birthday!!!!!!"

The 51-year-old Kidman is four months older than Urban. The couple have been married for 12 years and have two daughters together. This is just the latest public singalong featuring the pair. Several times they've shared a stage together, including at an album preview event in April where they split a microphone to sing "Parallel Line," a song from Urban's Graffiti U album.

Watch Keith Urban and Nicole Kidman Sing Together: 

Urban's Graffiti U World Tour with Kelsea Ballerini continues this week with stops in Clarkston, Mich., and Pittsburgh, Pa.

Kidman currently stars in a television series called Big Little Lies. Last fall she publicly wished her man a Happy 50th Birthday with a cute post on Facebook. Below an intimate photo she wrote: "Happy birthday to my husband, best friend, lover, baby daddy and the greatest man in the world. We are so lucky that you are ours. Love you from Nicole Mary, Sunday Rose & Faith Margaret xx."

Sunday Rose and Faith Margaret are their daughters.

Here are Some of Our Favorite Photos of Keith Urban and Nicole Kidman