The country crooner displayed a temporary tattoo she got at the Miami Express Yourself Oasis inspired by the promises her husband made to her on their big day while attending the Lollapalooza music festival this past weekend in Chicago – where Cibrian is also filming The Playboy Club.

"You gave me the courage to be truthful," the ink, etched on her ribcage, reads. "I promise to give you the comfort to be trustful."

Rimes says she's "just trying something, playing" for now – although it may be more permanent than she originally intended.

"Too funny!" she Tweeted. "I can't get it off. In search of rubbing alcohol I think!"

Cibrian, 38, and Rimes, 28, met on a movie set in 2008 and both ended their respective marriages to be together.