Britney Spears had her phone tapped and her home bugged by her conservators, according to a new documentary on the singer.

On Friday (September 24), the filmmakers behind the Framing Britney Spears documentary aired a surprise follow-up film titled Controlling Britney Spears on FX and Hulu.

After the first documentary dissected the singer’s conservatorship and the #FreeBritney movement, the follow-up promised to tell the story of the “intense surveillance apparatus that monitored every move the pop star made.”

NEW INSIDER REVELATIONS. @FXDocs & The New York Times Present: #ControllingBritneySpears. All-new TONIGHT at 10PM EST on FX. Stream on Hulu. pic.twitter.com/lLBExqdKKX

— Hulu (@hulu) September 24, 2021

In the new film, it is alleged Britney was under strict surveillance through her conservatorship, and New York Times journalists and the new documentary’s creators, Liz Day and Samantha Stark, spoke to Variety about the situation in a new interview.

“Britney speaking out in court was really the game changer, in terms of people saying they’re willing to break an NDA, or they felt it was important to speak,” Day said of getting people to speak for the documentary, which began shooting after Britney’s surprise testimony against her conservators in late June.

Asked how they felt when discovering these testimonies, Day added: “It was completely shocking. One of the reasons why it was so shocking is because we had heard rumours about this — people have speculated that her phone is bugged or her house is bugged, but no one really ever had proof.

“Security, in particular, was just a literal black box because no one knew what they did or how they operated. So, to have someone come forward with proof was so revealing and helps us understand how so much of what Britney said in court in June could be true. It’s hard to understand how that could happen to one of the most famous people on the planet.

Stark added: “A lot of people said, “Why wouldn’t Britney just say something? Or go on her Instagram and say something?” We are really starting to unravel how difficult that would have been, now that we know she had such an intense surveillance around her for all these years.

While many were supportive of first documentary Framing Britney Spears, Spears herself criticised the film, saying it was “hypocritical” in its invasion of her private life, and that she “didn’t like the way the documentaries bring up humiliating moments from the past.”

Director Samantha Stark then responded to the criticism, explaining how she “totally understands” Britney’s complaints.

• READ MORE: ‘Framing Britney Spears’: 10 key takeaways from the gripping new documentary

Reviewing Framing Britney Spears, NME wrote: “Framing Britney Spears acknowledges that ‘the real Britney’ is essentially unknowable at this stage: because she rarely gives interviews and has almost never spoken about her conservatorship on record, fans are left searching for coded messages in her superficially perky Instagram captions.

“And for obvious reasons, it offers no satisfying conclusion because Spears’ legal battle to rework the terms of her conservatorship is ongoing.”

Another documentary on the star, this one from Netflix and titled Britney vs. Spears, is coming out next week (September 28) – watch the trailer here.