Trail blazing Irish singer Sinead O'Connor offered some heartfelt advice in an open letter to Miley Cyrus this week only to be sneeringly rebuffed by the troubled 20-year-old.

In her open letter O'Connor warned the young singer not to allow herself to be sexually exploited by the music industry.

O'Connor was inspired to write the letter to Cyrus after learning that the 20 year old had modeled her recent Wrecking Ball video on O'Connor's famous video for Nothing Compares 2 U.

This week O'Connor bluntly told the former Hannah Montana child star that it's ultimately self-defeating to market her sexuality instead of just her music.

'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,' O'Connor wrote in reference to the Wrecking Ball video, which echoes Nothing Compares 2 U but has a far more sexualized content.

O'Connor, now 47, has always insisted that her music rather than her image be the selling point in her career. From the start she shaved her head and fought her own corner against any pressure to conform from the music  industry.

Rather than being molded for stardom by them, she created her own path, often successfully, but sometimes at her own peril. Along the way however she learned about the real agenda of the music business and now cautions 20-year-old Cyrus that she fears it will exploit her and then abandon her.

‘You are worth more than your body or your sexual appeal,’ wrote O’Connor. 'The world of showbiz doesn’t see things that way, they like things to be seen the other way, whether they are magazines who want you on their cover, or whatever.. Don’t be under any illusions.. ALL of them want you because they’re making money off your youth and your beauty.. which they could not do except for the fact your youth makes you blind to the evils of show business. If you have an innocent heart you can’t recognize those who do not.’

But Cyrus, whose recent antics have made headlines and prompted many to even express concern about her mental health, was not in a listening mood.

According to ABC Cyrus responded to O'Connor's letter on Twitter by crudely mentioning the Irish singer's struggles with bipolar disorder.

In a reference to troubled actress Amanda Bynes, who has recently been treated in a psychiatric hospital in California, Cyrus tweeted: 'Before Amanda Bynes...There was…' and she posted O'Connor's own tweets about seeking psychiatric help.

The move, which some have called unnecessarily heartless, has reportedly angered both Cyrus' fans and critics alike.

Here's the E! News report on Cryus' controversy: