"Its basic human decency to at the very least remove a person Britney has identified as abusive from her life," Azalea wrote. "This should be illegal."
The "Fancy" singer collaborated with Britney on the 2015 single "Pretty Girls," which the pair performed at that year's Billboard Music Awards.
"During the time we worked together in 2015, I personally witnessed the same behavior Britney detailed in regards to her father last week," Azalea claimed. "And I just want to back her up and tell the world that: She is not exaggerating or lying."
Azalea further claimed, "I saw her restricted from even the most bizarre and trivial things: like how many sodas she was allowed to drink. Why is that even Necessary?"
She also alleges that Jamie used the opportunity to force her to sign a non-disclosure agreement.
"Her father conveniently waited until literally moments before our [Billboard Music Awards] performance when I was backstage in the dressing room and told me if I did not sign an NDA he would not allow me on stage," Iggy claimed. "The way he went about getting me to sign a contract, sounded similar to the tactics Britney spoke about last week in regards to her Las Vegas show."
"Jamie Spears has a habit of making people sign documents while under Duress it seems, and Britney Spears should not be forced to co-exists with that man when she's made it clear it is negatively impacting her mental health," she continued. "This is not right at all."
ET has reached out to Jamie's team regarding Azalea's comments.
After sharing her statement, an interview resurfaced showing Iggy speaking with Andy Cohen on an episode of Watch What Happens Live in 2016, in which she said people from Britney's team searched her house before the singer came over for a lunch.
"They came and checked my place, to make sure I wasn't trying to stash anything weird, that I might give to her... To make sure I wasn't a bad influence," she shared, to Cohen's surprise. "And I'm not! I passed the test."
Britney appeared remotely to address a Los Angeles judge last week for the latest hearing on her conservatorship. During her testimony, she called out her father and alleged that the conservatorship holds her back from living her life.
The pop star expressed that she would like nothing more than "to end the conservatorship without being evaluated," as well as regain control of her life. Spears also shared a number of shocking allegations against both her father and his team, including how they allegedly forced her into rehab, made her work when sick, and how she isn't allowed to get married or have more children.
Following Britney's claims, Jamie's attorney said in a statement to the judge, "He is sorry to see his daughter suffering and in so much pain. Mr. Spears loves his daughter and misses her very much."
Jamie later asked in court documents obtained by ET that his daughter's claims be investigated as they are "serious allegations regarding forced labor, forced medical treatment and therapy, improper medical care, and limitations on personal rights."