Madonna, in the latest in a string of bizarre antics, exposed a fan's breast on stage yesterday during her concert in Brisbane, Australia.
The 57 year-old pop star, who is on her Rebel Heart world tour, had invited the female concert-goer to join her on stage.
"She's the kind of girl that you just want to slap on the a**," she said, "and pull..." as she yanked down the woman's corset-style top in front of thousands of fans.
"Oh s**t. Oh sorry, sexual harassment," she continued. "You can do the same to me if you like."
Her increasingly erratic behaviour comes as she fights her ex-husband, British film director Guy Ritchie in a custody battle over their 15-year-old son Rocco. The teenager has been living with his father in London since December after refusing to return to his mother's New York home.
At another concert in Brisbane on Wednesday, she showed up more than two hours late. She was also late to her performance yesterday.
And last week, the singer was accused of performing drunk on stage.
She had donned a wig, top hat and striped stockings to perform a special Tears Of A Clown show in Melbourne, outside of her Rebel Heart tour.
Video clips posted by audience members showed her at times to be stumbling and speaking erratically during the show - a contrast to her usual highly choreographed tours. She also fell off a tricycle during her performance.
She later posted a photo of herself drinking what her representatives said was one Cosmopolitan cocktail - usually made with vodka and cranberry juice - on stage.
In another Tears Of A Clown show two days later, she showed a large photo of Rocco as a young boy, telling the audience "I probably would have enjoyed myself a bit more on this tour if he hadn't disappeared so suddenly."