Sinead O’Connor is facing a $US5 million ($6 million) lawsuit after she alleged Prince had received drugs from a US talkshow host “over the decades” a week after the singer died from what is suspected to be a prescription drug overdose.

Arsenio Hall, who was the host of late-night talk show The Arsenio Hall Show from 1989 until 1994, is suing O’Connor for defamation over allegations made on her public Facebook account.

In a post published on Tuesday, the 49-year-old singer, whose most successful song was a cover of Prince’s Nothing Compares 2 U, said: “Anyone imagining Prince was not a long time hard drug user is living in a cloud cuckoo land”, before saying she had reported Hall to Minneapolis’ Carver County police department, who are  investigating Prince’s death.

The next day, O’Connor posted a 1400-word rant about Hall to the same page, seemingly referencing their interactions when she appeared on his talkshow ahead of her controversial 1991 Grammy Awards boycott.

Both posts remain live on her Facebook account.

The complaint filed by Hall’s lawyers on Thursday in the Los Angeles Superior Court describes O’Connor as a “desperate, attention-seeker … now known perhaps as much for her bizarre, unhinged internet rants as for her music”, the Hollywood Reporter reports.

“O’Connor knew that there was no truth whatsoever to the vicious lies she spewed about Hall on her Facebook page, and that she had concocted them and had no basis to believe that they were true,” the complaint reads, adding that as O’Connor has publicly acknowledged she only met the late singer a couple of times, she “would have no basis to have personal knowledge of anyone who may have allegedly provided Prince with illegal ‘hard drugs’ “.

The complaint seeks $US 5 million  in compensatory damages, as well as requesting a punitive amount of damages as a deterrence to others.