The conservatorship was put in place after Britney was involved in a string of high profile and highly publicised incidents from 2006 to 2008.
These included her shaving her head, being photographed in unflattering circumstances at a patrol station and, attacking a car with an umbrella.
At the same time, Britney was hotly pursued by paparazzi, and was a new mother. At the beginning of 2008, she entered into a custody battle with the father of her children, ex-husband Kevin Federline.
That same month, Britney was involuntary put into psychiatric care. By February, after almost two years of highly publicised public meltdowns, Britney's father Jamie was granted the temporary conservatorship of his daughter. Six months later, this conservatorship was made permanent, according to Fox Business.
A conservatorship is a status used in the US legal system, where an individual is considered to be legally under the care of another person, who is sometimes referred to as their "guardian".
It is put in place where a person is suffering from conditions that place limitations on their ability to care for themselves. The person might be suffering from a mental condition that in some way makes them unable to make decisions over some, or all parts of their lives.
While Britney's conservatorship has been in place since 2008, in May of this year, Britney met with a judge to discuss issues to do with the conservatorship. The judge ruled the conservatorship needed to be evaluated.
NEW CONSERVATOR APPROVED BY JUDGE IN LA
While the evaluation continues, Ms Montgomery, who has worked with Britney for the past 12 months as her care manager, has been granted the role of Britney's new conservator.
According to court documents obtained by Billboard, Ms Montgomery is "an experienced professional fiduciary with ability, experience, and support resources, to take on these obligations during this time and has been the care manager for Spears for approximately a year".
A Los Angeles judge approved the change on Monday.
If the court does find that Jamie's care of Britney was wanting, it's likely Lynne Spears, Britney's mother, or Kevin Federline, her ex-husband, will challenge the conservatorship that lasted more than a decade.
The issue has become so heated it has recently been at the centre of an online conspiracy, buffeted by the hashtag #freebritney.
In that case, it's likely Britney's father will be permanently removed from his role as the pop star's guardian.
It's worth remembering, before Britney sensationally cancelled her Britney: Domination Vegas residency in January, her conservatorship had largely been viewed as a handshake agreement between her and her father.
Despite being under the binding agreement, Britney had continued to tour, release music and make perfumes.
But Britney's Instagram post in January, announcing the cancellation of her upcoming residency in Vegas shocked many, and started a wave of fan's theorising wildly about Britney's personal freedom.
"I've been looking forward to this show and seeing all of you this year, so doing this breaks my heart," she wrote on Instagram. "However, it's important to always put your family first … and that's the decision I had to make."
#FREEBRITNEY CAMPAIGN LEADS TO DEATH THREATS
Since then, Britney's appearances have been the subject of intense public scrutiny. This included instances like a brief social media silence, following her tour announcement, which fans, using the #freeBritney hashtag, argued was suspicious.
Online, fan's alleged that Britney's tone was unusual, and argued that while under conservatorship, she was not in control of her posts. Fans have argued that Britney is secretly fighting for freedom from her conservatorship, which 11 years on, she has outgrown.
Online, at least, Britney has maintained that she is happy working out in her home, shopping at her local mall, at the gym and hanging at the beach with her boyfriend, 25-year-old Iranian-American model Sam Asghari.
But many of her fans remain unconvinced, leading Britney to eventually post direct responses to her fans.
A video Britney posted in April referred to her situation as "unique" but tried to reassure her fans she was "doing what's best at the moment". She also said her and her team had been receiving death threats.
Despite the furore, and fan campaigns, and unusual social media posts, months have sailed by, with little movement in the way of Britney's conservatorship.
But in the last week, a lot has changed.
JAMIE SPEARS' GUARDIAN ROLE IS REMOVED
Jamie Spears has been the legal conservator of Britney since 2008. His conservatorship was handed to him when his daughter was deeply in crisis, and gave him wide-ranging powers over Britney's freedoms.
He was reportedly given the ability to restrict and limit her visits, by any means. He was able to "retain caretakers and security for Britney on a 24-hour basis", he could prosecute civil harassment restraining orders, and could communicate with expert medical personnel regarding Britney and have full access to her medical and psychiatric records.
But on Monday, his role as conservator was removed and handed to Ms Montgomery.
Jamie has reportedly been criticised over the past year by others close to Britney over his ability to care for the pop star. Concerns have been raised over the cocktail of medication she was taking, which reportedly lost its efficacy earlier this year.
It was this failure in Britney's medical treatment that had lead to the popstar being hospitalised, according to TMZ.
In the lead up to the recent change in the conservatorship, the court ordered that Britney's medical care be investigated.
ACCUSATIONS OF ASSAULT
Britney's father has been accused of abusing her son, Sean, 13, an accusation that is now part of a criminal investigation.
The news was first reported by TMZ last week, a complaint was lodged to police by Sean's father, Kevin Federline. Law enforcement said the incident allegedly occurred at Britney's home in Ventura County, California.
Sean, 13, allegedly got into an argument with Jamie, and during which the older man reportedly broke down a door to get to the teenager, and put his hands on him.
Nobody was injured during the incident, however the teen was alarmed and reported it local Sheriff's department the following day.
The District Attorney is investigating the incident and will decide whether or not charge Jamie over the incident.
Britney and Federline's two sons, Sean and Jayden, 12, have reportedly now been granted restraining orders against Jamie, according to ET.
Federline and Britney had recently formalised a new child custody agreement, which allows Federline to have their children for 70 per cent of the time.
BRITNEY'S DOCTOR DIES
Britney's doctor, Dr Benson, passed away in Santa Monica, California last month. While the psychiatrist's cause of death is unknown, Dr Benson is believed to have died on August 24 after suffering an aneurysm, according to reports.
Dr Benson, 48, had been evaluated over that past three months by the court handling Britney's conservatorship, and was expected to hand over a report on Britney's care within the ten days of his death.
He had been scrutinised over his care of the pop star, after questions were raised over whether the pop star's medical and other specialist care had been appropriate.
According to TMZ, Britney's mother, Lynne, and other's involved had been critical of Jamie's handling of his role as conservator. Questions were raised around the medications Britney had been receiving, according to reports.
Dr Benson became well known after working with elite NBA and NFL athletes, according to TMZ. Sources close to Britney had argued that she needed a doctor who was available on a more full-time basis.
Britney was placed on a conservatorship after a series of highly publicised events in 2007. She went on to release another album, Circus, soon after the legal changes to her personal freedoms, in 2008.
In 2012, she earned $84,636,921 and was named the top earning female performer by Forbes magazine.
Another status hearing for Britney's continued conservatorship status is scheduled for September 18, according to Billboard.
