Keith Urban Rocks 'Nicole Kidman Arm Tattoo'

Nothing like wearing your heart on your sleeve! Er, arm.

With an audience of millions, Aussie country-rocker Keith Urban rolls up his sleeves and shows off his new NICOLE arm tattoo while rocking out to The Rolling Stones’ “Gimme Shelter” with soul songstress Alicia Keys during Live Earth New York at Giants Stadium on Saturday.

The Nicole arm tattoo obviously refers to his Aussie actress wife Nicole Kidman. Keith, 39, and Nicole, 40, celebrated their one-year wedding anniversary last month.

How romantic! Besides, if it doesn’t work out with Nicole Kidman, he can always find another Nicole. Kidding!

20+ pictures inside of Keith showing off his lady love on his arm…