The legendary painted-faced group KISS played a sold-out show at Nashville’s Sommet Center on Wednesday, and according to People.com Keith Urban and Nicole Kidman joined in the fun.

The celebrity couple pulled up to the backstage entrance, sneaking into the show under the radar. But once inside, they rocked out and “were adorable, smiling and totally low-key,” an onlooker tells us.

Seriously…these two get more in love every second.

Got some country music gossip and don’t wanna be a tattle tale?  Email me, Tawny Tucker, Tawny@countrymusictattletale.com