The singer has made several claims about Lynne Spears on the social media site, some of which relate to a stint she had at a medical facility
But why exactly does the couple appear to be at odds — and what did Britney Spears say on Instagram?
Here’s everything you need to know.
Who is Lynne Spears?
Lynne Spears, 67, is the mother of Britney Spears and her siblings Bryan and Jamie Lynn.
She married Britney Spears’ father, Jamie, in 1976.
Despite divorcing in 2002, the couple later reconciled and were together between 2010 and 2020.
She has written two books about her daughter and her family: heart to heart (2001) and Through the Storm: A True Story of Fame and Family in a Tabloid World (2008).
Why did Britney Spears fall out with Lynne Spears?
Britney and Lynne Spears appeared to be a close couple.
But on Monday (July 25) they clashed very publicly on social media site Instagram.
It started when Britney Spears posted screenshots of texts she sent her mother at a medical facility in 2019.
The messages, which were immediately deleted, related to the pop star being given a drug called Seroquel – a drug used to treat mental illness.
“He said he wants the Seraquil UP [sic] and i’m like whoaaaaaaa horsey go fk yourslwf [sic]’ was the message.
“I thought Seraquil was a sleep aid, but it’s stronger than lithium for bipolar disorder and WAAAAAY.”
It’s unclear whether Britney Spears was referring to her father, Jamie – whose conservatory covered his daughter’s health – or to a doctor.
In the now-deleted post’s caption, Britney claimed her mother and friend Jansen Fitzgerald did not respond to messages sent during her treatment – apparently against her will.
Ms Fitzgerald posted a screenshot of what appears to be her replying to messages from Ms Spears.
She said her “heart was a little broken” by her friend’s allegations and that she tried to help the pop star.
Lynne responded shortly after with a repost of Ms Fitzgerald’s picture and said she had replied to her daughter.
She insisted she was having “whole conversations,” but didn’t publicly disclose them.
“I feel sorry for you that you feel like the people who love you the most have betrayed you! Let me come to you! I love you!” she wrote.
The star’s mother didn’t publicly reveal her answers to her daughter.
What did Britney Spears say in the last Instagram post?
On Monday night (US time), Britney Spears took to social media again to accuse her mother of abuse.
The singer made several allegations against her mother, including claims that Lynne Spears orchestrated her admission to a medical facility in 2019 and also deprived her of caffeine and withheld her car keys.
She also insisted that her mother had not responded to her messages, despite Lynne’s previous insistence.
Lynne Spears has not publicly responded to her daughter’s allegations.