The feud between Sinead O'connor and Miley Cyrus has escalated into a potential legal battle.

It all began when the Irish singer sent Cyrus an open letter telling her not to 'prostitute' herself after Miley said in an interview with Rolling Stone that her 'Wrecking Ball' video was inspired by O'Connor's 'Nothing Compares 2 U' clip.

The twerking star didn't appreciate O'Connor's wise words and took to twitter to fire back at the 46 year old.

Miley's post read "Before Amanda Bynes.... There was....", obviously she was trying to mock the fact that O'Connor has bipolar disorder and she also retweeted posts from O'Connor asking her followers to recommend psychiatrists, but they were 2 years old.

Amanda Bynes, who Miley referred to, is currently undergoing psychiatric treatment.

O'Connor was appalled and incensed by her actions on the social media site and immediately posted a second open letter on her Facebook page. The letter begins by saying; "Miley. Really? Who the f**k is advising you? Because taking me on is even more f**kin' stupid than behaving like a prostitute and calling it feminism. You have posted today tweets of mine which are two years old, which were posted by me when I was unwell and seeking help so as to make them look like they are recent".

"I mean really really. who advises you? Have you any idea how stupid and dangerous it is to mock people for suffering illness?"

She also states in the letter "Remove your tweets immediately or you will hear from my lawyers".

The feud continued as Miley posted further tweets by writing, "I don't have time to write you an open letter cause I'm hosting & performing on SNL this week" and "So if you'd like to meet up and talk lemme know in your next letter. :)".

Following this was a third open letter by O'Connor posted yet again on her Facebook page which read, "I have no interest whatsoever in meeting you. You had plenty of time yesterday to abuse Amanda Bynes, an entirely innocent party, and myself, who also did nothing to deserve your abuse".

She also wrote "You can take five minutes today between g- string f**kin' changes to publicly apologise and remove your abusive tweets. If you do not then you don't give a s*** who you mock and what damage you do by being so ignorant".

'The Lion and The Cobra' singer does not seem to show signs of losing in this war of words and now the anticipation is building for another Miley response, but has the threat of legal action changed the tune of the outspoken Cyrus?

sinead o'connor
Sinéad O'Connor has threatened Cyrus with legal action

miley cyrus
Cyrus has took to twitter to respond to and mock O'Connor