Fans of singer Kesha (born Kesha Rose Sebert) have launched a petition asking Sony to release her from a contract that forces her to work alongside Dr Luke, amid a legal battle centred around lurid claims regarding the producer's behaviour.

The petition urges the record company to terminate Kesha's deal with Dr Luke's personal imprint, Kemosabe, which bars her from recording or releasing any music unless the producer is involved. The petition already has 85,000 signatures.

"It's our hope the court grants this injunction, but Sony can end all of this right now by voluntarily terminating Kesha's contract with Dr Luke," the petition, which is targeted at Sony boss Doug Morris, states.

As the legal battle continues, some fans have pledged to protest outside the New York courthouse on the day the trial in January. Within hours of the campaign's launch, #FreeKesha was trending on Twitter.

Back in October 2014, the 28-year-old singer filed a lawsuit in Los Angeles claiming that the music producer took advantage of her and threatened to harm her career during their decade-long professional relationship.

"She was terrified of speaking, messaging, tweeting or doing anything at all that he might disapprove of in the event that he would later use it to torture her and her family, as he had done so many times before," legal documents read.

Kesha's lawyer, Mark Geragos, added: "This lawsuit is a whole-hearted effort by Kesha to regain control of her music career and her personal freedom after suffering for 10 years as a victim of mental manipulation, emotional abuse and sexual assault at the hands of Dr Luke."

Dr Luke denies all allegations, describing them as "defamatory" and claiming they have been contrived in an attempt to extort him into releasing the singer from her contract. "Kesha and her mother are engaged in a campaign of publishing outrageous and untrue statements about Dr Luke to third parties, including scurrilous and false statements of purported physical and mental abuse of Kesha," said Dr Luke's lawyer, Christine Lepera.

The producer has filed a counter-claim, accusing Kesha and her mother of breach of contract and contractual interference.