A woman who accused R Kelly of sexual abuse says he wrote a letter threatening to reveal details of her sexual history if she did not drop a lawsuit.

Faith Rodgers and her lawyer Gloria Allred spoke on Monday at a news conference in New York.

Ms Allred said Kelly sent the letter in October to another of Ms Rodgers’ lawyers.

In the letter, a person identifying himself as R Kelly wrote that if the suit went forward, he would have “10 personal male witnesses” give evidence about Ms Rodgers’ sex life.

It said she should stop if she “really cares about her own reputation”.

The singer’s lawyer, Steve Greenberg, said the letter “looks fake”.

Kelly denies any misconduct. His career has been in turmoil since the airing of a documentary detailing accusations against him.

Faith Rodgers with her lawyer Gloria AllredFaith Rodgers with her lawyer Gloria Allred (Richard Drew/AP)

The letter said the singer would demand medical documentation of the woman’s claim that he gave her herpes and force her to turn over texts and social media posts.

“If Ms Rodgers really cares about her own reputation she should cease her participation and association with the organisers of this negative campaign,” the letter said.

Mr Greenberg said: “It obviously was not authored or signed by Mr Kelly, nor sent on his behalf. He doesn’t write letters.”

Steve GreenbergSteve Greenberg (Kiichiro Sato/AP)

The letter was sent a few weeks after the singer was served with the lawsuit accusing him of demeaning her, locking her in rooms and vehicles, and subjecting her to “non-permissive, painful and abusive sex”.

Ms Rodgers, 21, said she met Kelly as a 19-year-old after a concert in San Antonio. She participated in the recently aired Lifetime documentary Surviving R Kelly, which catalogued years of accusations against the singer.

“We are here today to let Mr Kelly know in no uncertain terms that he cannot and will not intimidate his alleged victims into keeping silent about their allegations,” Ms Allred said at the news conference.

“No woman should be victim-shamed, harassed or retaliated against because she asserted her rights and spoke her truth,” Ms Rodgers added.

The letter, sent to Ms Rodgers’ New York lawyer, Lydia Hills, also lectured her in sometimes nonsensical terms about her understanding of the law.

“This is to enlighten you concerning the presumption of court appearances that you may not be aware of since attorneys are taught a colouring of law and not Canon or Common Law. Color-of-Law is NOT law. It’s fiction for corporate fictions of which I am not.”

The letter writer added: “I am exempt and not subject to this court so I don’t know why you are even addressing me.”

Also on Monday, the Chicago Tribune published a story detailing court records it obtained on a July lawsuit seeking payment of 174,000 dollars in back rent and other costs for his Chicago recording studio.

The documents include a signed eviction notice, which was put on hold until January 21 for Kelly to pay.

The studio has been the site of recent protests against Kelly, with those involved calling on promoters to stop booking his concerts.