On Thursday night, Penn was spotted by an ET insider enjoying the second night of Madonna's Rebel Heart tour at Madison Square Garden in New York City. The 55-year-old actor didn't even appear awkward when the Material Girl performed her hit, "True Blue," which was inspired by him.
In fact, Madonna's former husband had a sweet smile on his face!
Madonna actually dedicated the entire True Blue album to Penn in 1986. "This is dedicated to my husband, the coolest guy in the universe," she wrote in the liner notes.
During her show, the 57-year-old music icon also admitted that she's not sure if she'll ever wed again. (She was married to director Guy Ritchie from 2000 to 2008.) Madonna joked that all the married and in love people in the audience were "suckers." She added, "But I'm still a romantic heart."