Miley Cyrus
Miley Cyrus has always been renowned for her controversial behaviour Danny Moloshok/Reuters

Pop superstar Miley Cyrus continues to employ shock tactics and sexualisation to aid her public reinvention, but she may have gone one step too far with her latest stunt. Fans of the former Hannah Montana actress have voiced their concerns over her mental health after she took to the stage wearing prosthetic breasts and a strap-on penis.

The 22-year-old singer made sure the opening night of her Dead Petz tour, aka the Milky Milky Milk Tour, in Chicago went down in history with an S&M-inspired look that came complete with a purple wig and a silver bondage harness. She performed tracks from her latest album for the first show on her six-date tour.

Thanks to a catalogue of controversial antics that includes stripping naked for her wrecking Ball video, and twerking on a then-married Robin Thicke at the 2014 MTV EMAs, Cyrus has successfully killed off her sweet girl image. Last year, she sparked outrage with her Bangerz tour when she groped backing dancers and encouraged her audience to smoke marijuana, and most recently she went full-frontal for a Terry Richardson spread featured in Candy Magazine.

Although Disney stars have a history of going through rebellious phases, following Miley's recent show her fans raised the alarm on social media. While some claimed she was just at her attention-seeking best, others claimed that her actions were a classic cry for help and suggested that she may be using drugs.

One unimpressed fans said: "Ok tbh what in gods name is wrong with Miley Cyrus now she used to sing The Best of Both Worlds & now she's literally eating glitter."

Cyrus previously admitted that she was never taught that drugs were bad, saying while some critics might slam her open use of marijuana as irresponsible, she doesn't see anything wrong with it.

"I put some picture of me smoking weed... on my Instagram, because I was brought up in the way that we never thought marijuana was bad," she said in an interview with Sunday Tonight. "You know what hurts your brain? Googling yourself. You know what hurts your brain? Instagram. You know what hurts your brain? Reading comments on Facebook. You know what hurts your brain? Reading US Weekly," she said.