Madonna exposes fan's breast onstage during concert

For pop provocateur Madonna, it's no longer enough to flash some nudity. She's now exposing other people's body parts, too.

The singer startled audience members by inviting a 17-year-old fan onstage during her concert Thursday night in Brisbane, Australia, and then tugging down the teen's corset top to briefly reveal her left breast.

"She's the kind of girl you just want to slap on the a** -- and pull," Madonna told the crowd before exposing the young fan. "Sorry ... sexual harassment. You can do the same to me. Good luck."

In videos posted online, the teenager appeared unfazed by the wardrobe malfunction and hugged Madonna seconds later. Afterward, she told Australian media that the episode was no big deal to her: "It was, seriously, nothing. I didn't think of it until everyone totally freaked out about it."

But some observers criticized the incident.

"Madonna is in total meltdown. She needs to cancel this tour asap," said TV journalist Piers Morgan, a former CNN host, on Twitter.

Other Twitter users wondered how people would react if Madonna were a male performer, and questioned whether what the singer did was a criminal act.

What Madonna did was disgusting and if it was a man that did that they'd be prosecuted so why should she get away with it?

— mєgan martinૐ (@__MeganMartinnx) March 18, 2016

The 57-year-old pop icon, who has long cultivated a brazenly sexual persona, has not commented on criticism of the incident.

It's the latest in a rash of erratic behavior by the Material Girl on her Rebel Heart tour, which wraps up Sunday in Sydney. She has begun concerts several hours late, spewed profanity onstage and made vulgar comments about ex-husband Guy Ritchie, with whom she is locked in a bitter battle over custody of their son Rocco, 15.

In recent months, the teen has been living in London with his father. Judging by some of Madonna's recent comments, being apart from her son has been hard for her.

"There's no love stronger than a mother for her son, and if I talk about him too much, I'm going to cry," the singer told the crowd this month during a concert in New Zealand, her voice cracking. "I hope he hears this somewhere and he knows how much I miss him."