Singer Sinead O'Connor has written an open letter to fellow singer and actress Miley Cyrus warning her not to be exploited by the music business.

The 46-year-old wrote to Cyrus, 20, after she cited O'Connor's video Nothing Compares 2 U as an inspiration for her explicit Wrecking Ball video.

O’Connor wrote "Nothing but harm will come in the long run, from allowing you to be exploited,”.

"Please, in future, say no when you are asked to prostitute yourself."

O'Connor said she was prompted to write, "in the spirit of motherliness" after "dodging phone calls from various newspapers" who wanted the singer-songwriter to comment upon similarities between the two videos.

The video for Nothing Compares 2 U is principally a close-up of O'Connor, who sheds a single tear as she performs the Prince-penned break-up ballad.

Cyrus cries in the promo clip for Wrecking Ball, which shares similar lyrical themes to O'Connor's song. But the video also finds her licking a sledgehammer and swinging naked on a metal demolition ball.

"I am happy to hear I am somewhat of a role model for you and I hope that because of that you will pay close attention to what I am telling you," wrote O'Connor.

"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.

"It is in fact the case that you will obscure your talent by allowing yourself to be pimped, whether it's the music business or yourself doing the pimping.

"It is absolutely NOT in ANY way an empowerment of yourself or any other young women, for you to send across the message that you are to be valued (even by you) more for your sexual appeal than your obvious talent.

"You are worth more than your body or your sexual appeal. The world of showbiz doesn't see things that way," continued the Irish singer.

"They're there for the money; we're there for the music. It has always been that way and it will always be that way. The sooner a young lady gets to know that, the sooner she can REALLY be in control."

Cyrus, who found fame as the child star of Disney children's show Hannah Montana, has been criticised in recent weeks for her controversial performances, most particularly at the MTV Video Music Awards in Brooklyn last month.

"You also said in Rolling Stone that your look is based on mine," wrote O'Connor. "The look I chose, I chose on purpose at a time when my record company were encouraging me to do what you have done.

"I felt I would rather be judged on my talent and not my looks.

"I am happy that I made that choice, not least because I do not find myself on the proverbial rag heap now that I am almost 47 years of age.

"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," concluded O'Connor.

"The message you keep sending is that it's somehow cool to be prostituted. It’s so not cool Miley, it’s dangerous."