The mother of pop star Kesha has broken her silence, speaking out about her daughter's more than 10-year relationship with producer Dr Luke, who is accused of sexually assaulting the singer.

Rosemary Patricia 'Pebe' Sebert, 60, of Nashville described her 29-year-old daughter as 'a prisoner' and said the senior producer constantly criticized Kesha and compared her to Katy Perry.

'Luke almost destroyed us,' Sebert said an exclusive interview with Billboard. 'And he has done it intentionally.'

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Rosemary Patricia 'Pebe' Sebert, 60, (pictured) the mother Kesha has broken her silence about her daughter's more than 10-year relationship with producer Dr Luke, who is accused of sexually assaulting the singer

Kesha pictured leaving court last month with her mother pictured on the steps behind her. In a recent interview, Sebert described Kesha as 'a prisoner' regarding her relationship with Dr Luke

The interview comes just a day after a report claimed that Sony is set to drop Dr Luke, 42, from the firm amid outrage over the sexual assault claims against him.

Last month, Kesha sat in court sobbing as a judge denied a preliminary injunction that would have allowed her to record music outside of her six-album contract with Dr Luke, whose real name is Lukasz Sebastian Gottwald.

Kesha filed a lawsuit in October 2014 against him which claims he drugged and raped raped her, and also controlled and psychologically abused her from the time she moved to Los Angeles in 2005 to pursue her music career to her breakthrough in 2010 and beyond.

'She was a prisoner,' Sebert, a songwriter who has written hits for artists including Dolly Parton and Johnny Cash, said of her platinum-selling artist daughter.

'It was like someone who beats you every day and hangs you from a chain and then comes in and gives you a piece of bread. Luke would say, "You look nice today" and send her into ­hysterics of happiness because she was programmed to expect nothing but abuse.'

In 2005, the pop singer dropped out of her Nashville high school before moving to Los Angeles where she signed her deal with Lukas and his company Kasz Money when she was 18.

According to her lawsuit, Kesha claims the producer raped her in October 2005 after they had attended a birthday party for Nicky Hilton, where she had been drinking, before he gave her GHB, what he called 'sober pills'.

Sebert pictured in 2011. 'Luke almost destroyed us,' she said in a recent interview. 'And he has done it intentionally'

The drug, according to the lawsuit, is what allowed him 'bring [her] back to his hotel room alone and rape her while she was unconscious.'

Documents do not specify a date of the alleged rape, but Sebert claims Dr Luke drugged Kesha at the Hiltons' party on October 5, 2005 and then took her back to his hotel room that night.

The day after, Sebert told Billboard that she had grown concerned after not getting a response from Kesha after calling her several times.

She said in the interview that Kesha finally returned her call, telling her she had woken up naked in what she thought was Dr Luke's hotel room.

Sebert said her daughter told her, 'Mom I don't know where I am. I think we had sex. I'm sore and sick. I don't know where my clothes are. I think I need to go to the hospital.'

Then Kesha's phone died as Sebert kept calling her daughter until she finally called back from the hotel's landline.

A friend of Kesha's eventually picked her up and took her back to her apartment, according to Sebert.

'Looking back, I don't know why we didn't go to the police,' Sebert said.

'Kesha told me not to do anything. She said, "Mom, I just want to sing. I don't want to be a rape-case victim. I just want to get my music out." I didn't follow my instincts.'

Dr Luke has vehemently denied allegations that he sexually assaulted Kesha and in a sworn statement last December called the claims untrue.

The producer has been nominated for four Grammy Awards and among his accolades has also co-written and co-produced 16 No 1 singes including Katy Perry's hits Teenage Dream and Roar.

A music manager who has known Dr Luke for more than 20 years told Billboard that he is talented but described him as a 'terrible person' and said 'no one likes dealing with the guy.'

Meanwhile, veteran publicist Elizabeth Freund who has known Luke, who is not her client, since he was 11 years old when she was his sister's camp counselor, told Billboard that 'there's not one speck of doubt in my mind that he didn't commit these allegations.'

She also described him as a 'strong, kind and a loving and utterly good man.'

'All of their horrific allegations of abuse, threats and purported misconduct by me against Kesha are ­completely untrue and deeply hurtful,' Dr Luke said in a statement.

Luke's attorney Christine Lepera added that the pop singer's court filings 'are and have always been a transparent business ploy to pressure Luke into a more favorable and lucrative contract.'

'Neither Kesha nor her mother have ever sworn under oath that any of the assault allegations have occurred, despite having numerous opportunities to do so,' Lepera said in a statement.

'In fact, they swore the opposite in 2011.'

Lepera referenced an unrelated 2010 lawsuit also involving Dr Luke in which Kesha testified that Dr Luke never gave her a 'roofie' or coerced her into sex.

Sebert also gave a deposition claiming the producer did not ever give Kesha drugs and that she was not aware of any sexual relationship between him and her daughter.

Sony is set to drop Dr Luke (left) from the firm amid outrage over claims he sexually assaulted pop singer Kesha (right), a report claims

Dr Luke commented on the allegations on Twitter writing that 'it's sad that [Kesha] would turn a contract negotiation into something so horrendous and untrue.'

He also said that he feels 'confident that when this is over the lies will be exposed and the truth will prevail.'

According to Billboard, a Sony representative said that following an internal investigation, they found no evidence to support Kesha's allegations of sexual abuse.

'I wanted Kesha to come forward a long time ago and end this relationship with Dr. Luke immediately after the [alleged] rape,' Sebert said.

'But if she wanted to have a shot at the music business, she had no choice but [to work with him].'

Months following the alleged rape, Kesha signed David Sonenberg at DAS Communications as her manager, who has worked with the Black Eyed Peas and The Fugees, as she searched for a record deal.

Kesha nearly had a deal with Warner Bros through A&R executive Kara DioGuardi, who is also a former American Idol judge.

DioGuardi confirmed that Warner Bros and Arthouse Publishing had signed an agreement with Kesha for recording rights but said Dr Luke called her to say he had a pre-existing contract with her, and shortly after they decided to release her from their agreement.

After the failed deal with Warner Bros, Sebert said that Kesha started making suicidal claims.

'Kesha would tell me she was going to take her car to Mulholland and drive off the cliff,' Sebert said in the interview.

'She was a little dramatic, but I never knew for sure.'

Sebert said one day Kesha called asking what she should do saying, 'Dr. Luke just called me and I have 24 hours to fire my lawyer and my ­managers and go back with him.

'Anytime I get a contract, he's going to come ­forward and basically say he owns me.'

A few years later, Kesha eventually made her first appearance on Flo Rida's single, Right Round, which became a No 1 hit in early 2009.

Around that time, Dr Luke had flown with Kesha to New York to shop for a record deal and while there she eventually signed to RCA, a division of Sony Music.

Sebert said in the interview that she does not know why they did not go to the police and that Kesha had told her not to do anything. She said, "Mom, I just want to sing. I don't want to be a rape-case victim. I just want to get my music out." I didn't follow my instincts.'

Kesha pictured leaving court on February 19. A judge denied a preliminary injunction that would have allowed her to record music outside of her six-album contract with Dr Luke

Prior to a flight to Los Angeles, Kesha claims in her lawsuit that Dr Luke forced her to snort an 'illicit drug' and made sexual advances on her while she was intoxicated on the plane, where she had been drinking.

'I do remember her calling me from the plane telling me that she was so drunk, and [how] Dr Luke came over and started making out with her and was all over her,' Sebert said.

'She told me she felt terrible and was trying to get away from him and then vomited.'

Sebert also claimed that the producer interfered with her personal and professional relationship with her daughter while Kesha was recording Animal, her debut album.

He reportedly refused to let her work on the music, even though he made promises that he would let her.

Sebert sent emails to Dr Luke and his team in 2013, which she showed to Billboard, regarding the mistreatment Kesha was enduring from the producer, including the alleged rape, but Sebert said he never responded.

In early 2010, the pop star's career exploded with her debut single, Tik Tok, which was No. 1 on the Hot 100.

Her debut album, Animal, also went on to be No 1 on the Billboard 200 and reportedly sold 1.5 million copies.

And with her success, Dr Luke's focus on her only intensified, according to Sebert.

'This is when Luke started getting really hateful,' she said in the interview.

'He saw her as a cash cow and started manipulating her all the time. She thought all her dreams were finally coming true, but this was just a f***ing trip to hell.'

According to the mother, Dr Luke would comment on how Kesha was not fit enough and would reference Katy Perry, saying she was better than her.

After working long hours in the studio, Sebert said he would say things to Kesha such as 'Katy Perry is so much better than you. You're not a good writer.'

Sebert said Dr Luke would comment on how Kesha was not fit enough and would reference Katy Perry, saying she was better than her. The pair pictured together in 2010

Sebert noted that Perry and her daughter, 'before they both got famous,' were once close friends.

Kesha, who battled with bulimia, claimed in the lawsuit that Dr Luke '­ridiculed' her body and weight 'to the point where I almost killed myself,' and 'encouraged her not to eat.'

Sebert said in one song he wanted Kesha to sing a lyric that included the phrase, 'some fat b****es in the bar,' but when she refused, Sebert said he backed Kesha into a corner, shaking his fist while screaming at her.

Kesha then bolted out of the studio and ran barefoot down the Pacific Coast Highway crying before climbing up nearby mountains where she hid so he could not find her, the lawsuit states.

Sebert said Kesha then called her manager to come pick her up.

In another incident, a photo shoot for the music video Die Young, Dr Luke allegedly called Kesha a 'fat f***ing refrigerator.'

Sebert said Dr Luke had made the comment to the video's director after Kesha was in her bra and underwear and was laying down for a scene.

She said her daughter would cry and say, 'I would rather be dead than spend one more day with him.'

Sebert also recalled a night in 2012 when she and Kesha had gone to the producer's studio where he screamed at them for three hours.

After Kesha asked him if she could go to the bathroom, she instead fled to the car where she proceeded to text her mom, 'Mom I'm not kidding. We are going to Mexico. F*** the music business.'

A year later, Kesha saw more success as she co-headlined a tour with Pitbull after his song Timber - featuring Kesha and co-written by Dr Luke, Sebert and others - was No 1 on the Hot 100 for three weeks.

However after personal struggles she entered the rehab facility Timberline Knolls in Chicago in January 2014 for her eating disorder.

A week later, she was joined there by Sebert who herself had previously sought treatment for an eating disorder and alcoholism. She said bulimia is a control issue.

Kesha pictured above as she receives her Visibility award from fellow performer Stephen Wrabel at the 21st Annual HRC Nashville Equality Dinner at the Renaissance Hotel on in Nashville on March 5

As she accepted the award, she delivered an emotional speech about growing up a misfit and told others 'don't be afraid to speak up against any injustice you experience'

'I really believe that the further this thing got with Dr. Luke, the less control she had and the worse her bulimia got, because it was the only thing [that gave her] control,' Sebert said.

Sebert said that Kesha underwent a lot of therapy since going to rehab and that she knew she 'couldn't go on as a healthy person' without breaking times from Dr Luke.

Kesha was no longer 'willing to be a victim,' according to Sebert.

According to the lawsuit, Kesha claims that Dr Luke repeatedly threatened that if she told anyone about the abusive incidents, he would destroy both her and her 'entire family.'

The suit claims he once took her to a beach 'to have a talk' and 'threatened to shut her career down and take away all her publishing and recording rights' and also allegedly threatened to harm Sebert and the entire family's careers 'as well as their physical safety.'

Sebert said that the threats left her daughter 'genuinely scared,' noting she would sometimes hire security to sit in the driveway of her Nashville home.

'Dr. Luke basically owns Kesha until her death,' Sebert said in the interview.

'He doesn't have to give her any money and is under no time constraints. She can't legally put any new music out, or he can and will sue her.'

In the wake of a court's decision to not free Kesha from her contract with Sony, a host of stars have flocked to get behind the fast growing #FreeKesha campaign joining Taylor Swift and Lady Gaga who have long expressed their support for the singer.

Sebert noted that Kesha initially thought it was a 'scammer' after receiving an email from Taylor Swift's publicist saying the singer was donating $250,000 to help Kesha with her legal troubles.

'It was really random,' Sebert said in the interview of the email about Swift's offer.

'Kesha was like, "Are you sure it's not some scammer?'"And then she said, "I would be honored if she wants to do that."'

Dr Luke quoted an extract from the memoir of record producer Clive Davis where he said Clarkson didn't like taking direction

Sebert noted that her daughter and Swift spoke directly, later.

Kesha has not released any music of her own since her 2012 album, Warrior, as she refuses to work with Dr Luke and Sony Music, his partner.

Sebert explained that Kesha is allowed to work with another producer, a fact confirmed by Sony, Billboard reported.

'But Luke gets to approve them,' she said.

'He gets to approve of anyone she works with. He has final say over everything.'

Meanwhile a lawyer for Sony has said the firm it is doing everything it can to support the artist in these circumstances, adding that it is 'legally unable' to end the contract to which it is not a party.

Sebert said that her daughter has been living in a new home in Los Angeles and has been working on music, she has 30 songs already written, and has also been spending time with family.

Kesha was on vacation with her longtime boyfriend, 28-year-old Brad Ashenfelter when she traveled to Nashville to accept the Human Rights Campaign's Visibility Award on March 5.

As she accepted the award, she delivered an emotional speech about growing up a misfit and told others 'don't be afraid to speak up against any injustice you experience.'

Sebert believes that Kesha needed to go public with her struggles in order to get healthy again, and noted that her daughter is 'so much better now.'

'She wasn't comfortable with having to do this, but I think she realized as this thing progressed that she can advocate for sexual abuse or other things,' she said.

'The fact that she is at peace with that has really been healing.'

Dr Luke has another year left on his five-year contract with Sony.

However, inside sources told The Wrap on Wednesday that the public saga has driven them to cut off the hit-maker.

'The fact that this hasn't already been taken care of is confusing, especially for people in the building,' a source described as a 'knowledgeable individual' told The Wrap.

'There is no contest. Kesha has no case in regards to her contract but they can't afford the Adeles of the world out in the streets calling the label unsupportive,' the insider continued.

Kesha has been begging a court to release her from her contract with Sony, so she does not have to work with him.

Another source told the site: 'Somebody has been convicted via Twitter. No court has convicted this person, so there may not be any legal basis to terminate an agreement. It would have to be mutual.'

Insiders speculate the firm would strike a negotiated departure with Dr Luke.

Sony told Daily Mail Online the firm has 'no comment' on the allegations in The Wrap. Dr Luke's attorney has yet to respond to Daily Mail Online's request for a comment.

His attorney, Lepera, allegedly told TMZ the claims are unfounded.

'Luke has an excellent relationship with Sony,' Lepera said, according to TMZ. 'His representatives are in regular contact with executives at the highest levels at Sony, and this has never come up.'

The development comes after Kelly Clarkson claimed she was blackmailed into working with Dr Luke by quoting a music executive who said she 'didn't like taking direction'.

Clarkson, who collaborated with Dr Luke on her records Since U Been Gone and Behind These Hazel Eyes, was asked about her experiences of working with him during an interview on Australian radio.

She responded by saying she was 'blackmailed' into working with him and said he was 'not a good person'.

A spokesman for Dr Luke, who runs Kemosabe Records for Sony Music, hit back at Clarkson's accusations by quoting an extract from the 2013 memoir of Sony Music chief Clive Davis.

And in the extract from the book, called The Soundtrack To My Life, Mr Davis claims Clarkson 'wasn't keen' on taking direction in the studio.

In the extract released by Dr Luke, it read: 'The fact is that I wanted Kelly to have those songs for the very reason he had written them. Both songs had a sharp rock edge, but were still capable of being pop hits.

'They would push Kelly in a promising direction for her, while maintaining and even growing her audience. Max and Luke are very strong, hands-on producers in the studio. They are intent on getting perfect vocal performances, and are relentless in that pursuit.

Lady Gaga performed the nominee for Best Original Song, Til It Happens to You, a song she dedicated to fellow popstar Kesha and to the millions of rape victims around the world

Other stars including Adele and Taylor Swift have also come out in support of Kesha and her bid to be released from her Sony contract

'It was hard for Kelly, who had come from the high of winning 'American Idol' and then having a double platinum album. But then suddenly you are in an entirely different world of making records in a studio, and you have to take direction. Kelly didn't like that.'

The statement containing the extract from the book came Clarkson told Australia's KIIS fM, she was blackmailed into working with Dr Luke by her label.

She said: ''It was a really hard time for me.

'They were like, 'We will not put you're label out if you don't do this'.'

With her entire touring crew financially dependent on her, the 33-year-old musician said she felt pressured to cave into her label's demand.

'We have a whole crew to support...people that depend on us for their livelihood so sometimes you have to make decisions that you just have to swallow that pill.'

And although Clarkson wouldn't be drawn to comment on Kesha's situation - as she said has no first hand knowledge of it - she offered that: 'I can remark on his character'.

'We've clashed before... He's difficult to work with, he's kind of demeaning,' she said.

'Unfortunately when you have that poor a character that so many artists don't like you, that's not normal.'

Drawing on her own personal experience working with the producer she added: 'Obviously he's a talented dude but he's lied a lot.

'Musically it's been really hard for me because he will just lie to people and it makes the artist look bad.'

In the wake of a court's decision to not free Kesha from her contract with Sony, a host of stars have flocked to get behind the fast growing #FreeKesha campaign joining Taylor Swift and Lady Gaga who have long expressed their support for the singer.

Adele became the latest big name to publicly support Kesha while picking up one of her four Brit Awards in London.