Britney Spears condemns sister Jamie Lynn in scathing Instagram post: 'You’re lying through your teeth about me'

Britney Spears is calling out younger sister Jamie Lynn Spears on social media again.

On Saturday, the pop star, 40, posted a set of videos from The Real and The Talk that showed the shows' hosts discussing the controversial battle between the Spears siblings, and the concept of family loyalty. In the caption of her post Spears spoke out about her sister and her new book, Things I Should Have Said.

"National bestseller???? DUH… the timing of your book was unbelievable Jamie Lynn … especially knowing the whole world had no clue what was really done to me!!!!" the pop star wrote. "My whole family including you is saying YOU DIDN’T KNOW … Bulls***!!!"

She added that she's "just kinda shocked that more people like these real soul sisters aren’t telling it like it is!!!"

She continued to accuse her sister of lying and taking advantage of her, writing, "the nerve of you to sell a book now and talk s***! I wish you would take a lie detector test so all these masses of people see you’re lying through your teeth about me!!!! I wish the almighty Lord would could come down and show this whole world that you’re lying and making money off of me!!!!"

Earlier this month, Spears called Jamie Lynn a "scum person" who made up "lies" to sell a "Hollywood book" in a scathing Instagram post, Yahoo Entertainment previously reported.

She also took to Twitter to condemn Jamie Lynn, stating that her sister "stooped to a new level of LOW" by claiming in her book that her sister exhibited "erratic," "paranoid" and "spiraling" behavior and once "locked them in a room with a knife," leaving the younger Spears "afraid." Jamie Lynn also claimed they got in a fight during the pandemic in which Spears allegedly "came at me," yelling in front of the former Zoey 101 star's two kids.

"You've stooped to a whole new level of LOW," Spears wrote on Twitter. "I've never been around you ever with a knife or would I ever even think to do such!!"

Spears also asked Jamie Lynn to "please, please stop with these crazy lies for the Hollywood books," adding "only a scum person would make up such things about someone."

The battle between the siblings escalated as a result of Jamie Lynn's interview with ABC News earlier this month. In the interview, Jamie Lynn said she attempted to help her sister get out of her conservatorship, but said the pop star wasn't making enough of an effort herself. Jamie Lynn also claimed she didn't have access to her sister's money. Subsequently, Spears took to social media yet again, claiming on Twitter that Jamie Lynn was selling "a book at my expense."

In another post, Spears said her "family ruined my dreams 100 billion percent and try to make me look like the crazy one... My family loves to pull me down and hurt me always so I am disgusted with them." She later said that Jamie Lynn "never had to work for anything."

In an Instagram story, Jamie Lynn defended herself.

"It's become exhausting when conversations, and texts we have in private don't match what you post on social media," Jamie Lynn wrote, Yahoo Entertainment previously reported. "I know you're going through a lot and I never want to diminish that, but I also can't diminish myself." She went on to say that "the things being said are absolutely not the truth, and I have to clarify that, because now it's getting harder for me to rationalize to my oldest daughter why our family continues to get death threats, as a result of their aunt's vague and accusatory posts, especially when we know she could tell the truth, and put an end to all of it in one second if she wanted to."

Jamie Lynn continued, "I hate to burst my sister's bubble, but my book is not about her. I can't help that I was born a Spears too, and that some of my experiences involve my sister. I've worked hard since before I was even a teenager, and I've built my career in spite of just being someone's little sister."