Madonna gushed about her ex-husband Sean Penn during her "Rebel Hearts" tour stop at the Barclays Center in Brooklyn, NY on Saturday night. The singer opened up to her audience about Penn, how he attended her show a couple days earlier at Madison Square Garden and the note he sent her afterwards.

"I did a show at Madison Square Garden the other night if you heard about it. And my ex-husband was there! Could you imagine?" she said to the crowd. "He had been at my show 30 years earlier when I was at Madison Square Garden, and he was very upset with me for wearing a costume that was too revealing. That's not a lie," she added.

Madonna said that after Penn witnessed her perform, he wrote her a note and said he "appreciates" her art.

"And that is what I have to say about marriage, OK? Thirty f--king years later," Madonna finished.

Penn and Madonna married on the singer's 27th birthday in 1985, and were married for four years. During their marriage, Madonna dedicated her 1986 album "True Blue" to Penn.

"This is dedicated to my husband, the coolest guy in the universe," she wrote in the album's dedication. She even performed the song "True Blue" at her Madison Square Garden show with Penn in attendance.

Despite their divorce, the former couple remained close friends over the years.

"I'm very friendly with my first ex-wife," Penn said in an interview for Esquire U.K.'s March issue.

Check out the video below!