Grammy nominee Iggy - who shares 2015 hit, Pretty Girls with Britney - has argued back after being criticised for not publicly speaking out about the pop-star's freedom.
The 31-year-old said that she had already privately 'reached out' to Britney, adding that she didn't think a public statement was the most "mindful" way to do it.
She added, when asked to 'tell all' on Twitter: "I signed a non-disclosure and her father could and probably would sue me."
"I said her team wouldn't let her do promo and that they went through my house etc and y'all said I was a hater," the Australian star wrote in another post on Twitter.
"I am actually here to support someone in a way that's helpful and also mindful.
"Britney has said in her own words, she's embarrassed to even share this with the world. If she needed me to speak on her behalf, that message has been delivered to her. Other than that - I'm good.
"I've done what I'm supposed to do, I've reached out. I'm not supposed to be mindlessly telling you all whatever was happening because half of these people are just here for entertainment not to help."
She added: "I actually care and she can use me if she needs my voice. Leave me alone PLEASE."
Britney has been locked in her conservatorship since 2008 following admission into a psychiatric facility.
During her court address last Wednesday, Britney gave a damning criticism of her father, management and all those currently in charge of her, and likened her conservatorship to "slave labour".
Her father, Jamie, has had total stewardship over the Britney's $60 million fortune, as well as having had the power to make medical decisions and business deals on her behalf. Jamie was then forced to split control with an attorney and a trust group in 2019.
In her statement, Britney told a very different story of her conservatorship from the smiles we see on Instagram, branding it "abusive", and expressing desires to "sue [her] family".
She told a judge she had been forced to work against her will, made to attend three counselling sessions a week and banned from doing simple things like seeing certain friends and being driven around by her boyfriend.
Perhaps most damningly, Britney talked of how her conservatorship was controlling her body, too. She told the court she had an IUD fitted against her will, so she wasn't able to have another child, despite her wishes to.
"I am not happy, I can't sleep. I'm so angry, it's insane. And I'm depressed," she said during the hearing.
"My dad and anyone involved in this conservatorship, including my management ... they should be in jail.
"I just want my life back. All I want is to own my money and for my boyfriend to be able to drive me in his car. I want to sue my family.
The mother-of-two added: "It's not okay to force me to do anything I don't want to. The conservatorship should end. I truly believe this conservatorship is abusive."
Jamie has since responded to Britney's new bombshell claims, telling the court that he "loves his daughter".
"He is sorry to see is daughter suffering and in so much pain," the statement read. "Mr Spears loves his daughter very much."
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