US comedian Arsenio Hall has filed a US$5m (€4.3m) lawsuit against Irish singer Sinead O'Connor after she accused him of supplying drugs to Prince.

O'Connor, whose best-known song 'Nothing Compares 2 U' was written by the late musician, made the allegations in a Facebook post.

She said she had reported Hall to investigators, adding that he should "expect their call".

Hall, who is best known for his late night US talk show in the late 1980s and early 1990s, has described the accusations as "despicable, fabricated lies".

The lawsuit, filed in LA on Thursday, states: "Desperate, attention seeker Sinead O'Connor has maliciously published outlandish defamatory lies about comedian Arsenio Hall, falsely accusing him of supplying illegal 'hard drugs' 'over the decades' to the recently deceased music artist, Prince, and of spiking her with drugs once years ago".

Hall has asked for a jury trial, estimating the damage to his reputation to be worth "not less than" US$5m (€4.3m).

It is not the first time O'Connor has courted controversy through comments on her website and social media.

In 2013, she expressed concern that Miley Cyrus had allowed herself to be "prostituted" by the music industry.

Cyrus responded by appearing to mock O'Connor's mental health problems. O'Connor has been public about her struggle with depression.

Authorities investigating Prince's final moments have still not released a cause of death for the 57-year-old pop icon.

An expert in treating addiction to painkillers had been asked to rush to his Paisley Park estate in the Minneapolis area shortly before the singer was found unconscious, it was revealed this week.