The "Toxic" singer, 40, slammed her younger sister on Friday, Jan. 14, after the Zoey 101 alum, 30, appeared on ABC News to promote her new memoir, Things I Should Have Said. On air, Jamie Lynn explained why she included a claim that Britney once took a knife and locked the two of them in a room together. According to Jamie Lynn, she was "scared" during the alleged incident and the resulting experience spoke to her "own panic attacks."
In a statement released on Twitter, Britney responded to the allegation and said that Jamie Lynn "stooped to a whole new level of LOW."
"I've never been around you ever with a knife or would I ever even think to do such !!!" she wrote. "The only knife I ever saw you with at home was cutting the biggest piece of squash I ever saw in my life and it was way too big for me to cut … So please please stop with these crazy lies for the Hollywood books !!!"
"NOW and only NOW I do know only a scum person would make up such things about someone," Britney continued. "I'm actually very confused about you making that up because it's honestly not like you at all !!!!"
She added in what appeared to be a sarcastic remark, "Congrats on introducing your older sister [to] the concept of getting LOW … LOWER … LOWEST … because you win on that one, babe !!!!"
The pop star and her sibling have been engaged in a public war of words ever since Jamie Lynn's interview aired on Jan. 12. During the candid sit-down with Juju Chang, Jamie Lynn addressed her family's "complicated dynamics" and said that she "didn't understand what was happening" when Britney was placed in a conservatorship more than 13 years ago.
"First off, I don't understand—when it was put into place, I was a 17-year-old—I was about to have a baby," said Jamie Lynn, who was pregnant at the time with her eldest daughter Maddie. "I was focused on the fact that I was a 17-year-old about to have a baby. I understand just as little about it then as I do now."
Britney's conservatorship, which had been largely overseen by her father Jamie Spears, was terminated in November. In a previous statement issued to E! News through his attorney, Jamie said in part that he "has tried to do what is in [Britney's] best interests, whether as a conservator or her father."
A day after Jamie Lynn's televised interview, Britney took to Twitter and said that some of her sister's comments "did bother me."
"My sister said was how my behavior was out of control," Britney wrote in a Jan. 13 post. "She was never around me much 15 years ago at that time …. So why are they even talking about that unless she wants to sell a book at my expense ??? REALLY ???"
In the scathing message, the Grammy winner also claimed that Jamie Lynn "never had to work for anything," adding that her family "loves to pull me down and hurt me always so I am disgusted with them."
Jamie Lynn later personally addressed Britney in a statement released earlier on Jan. 14, saying, "Last thing I want to be is doing this, but here we are. It's hard to see these posts, as I know the world also feels. I just wish her well. Brit, I am always here, you know behind the scenes I have always been here."
"It's become exhausting when conversations, and texts we have in private don't match what you post on social media," she shared. "I know you're going through a lot, and I never want to diminish that, but I also can't diminish myself."
The Sweet Magnolias star added, "That being said, 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."
E! News reached out to Jamie Lynn's rep for comment but has not heard back.