The 46-year-old singer has responded to the 'Wrecking Ball' star's recent revelation she modelled the controversial video for her song after Sinead's 'Nothing Compares 2 U' visual, insisting her provocative antics of late will ''harm'' her in the ''long run''.
In an open letter on her official website, Sinead pleads with Miley, 20, to let her talent speak for itself and not shed her clothes in order to get away from her child-friendly Hannah Montana image.
She wrote: ''I am extremely concerned for you that those around you have led you to believe, or encouraged you in your own belief, that it is in any way 'cool' to be naked and licking sledgehammers in your videos.
''The music business doesn't give a s**t about you, or any of us. They will prostitute you for all you are worth and cleverly make you think it's what YOU wanted ... and when you end up in rehab as a result of being prostituted, 'they' will be sunning themselves on their yachts in Antigua, which they bought by selling your body and you will find yourself very alone.''
Sinead also tells Miley - who caused outrage by twerking in a latex bikini while rubbing herself with a foam finger at the MTV Video Music Awards in August - she doesn't need the scantily clad theatrics to be successful.
She continued: ''You are worth more than your body or your sexual appeal. You have enough talent that you don't need to let the music business make a prostitute of you. Please in future say no when you are asked to prostitute yourself.''
The musician also argues the former 'Hannah Montana' child star is sending a ''dangerous'' message to her fans with her sexually charged image
She added: ''Whether we like it or not, us females in the industry are role models and as such we have to be extremely careful what messages we send to other women. The message you keep sending is that it's somehow cool to be prostituted ... it's so not cool, Miley. It's dangerous. Women are to be valued for so much more than their sexuality.''
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The film is expected to continue without Mendes' involvement.