Britney Spears has accused her sister of spreading "crazy lies" about her.

Britney Spears has slammed her sister on social media

Britney Spears has slammed her sister on social media

The 40-year-old pop star has taken to Twitter to hit back at Jamie Lynn Spears' recent alleging, with Britney suggesting that she's using her name to promote her new memoir, 'Things I Should Have Said'.

Britney said: "Jamie Lynn... congrats babe! [applause emoji] You've 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!! The only knife [knife emoji] I ever saw you with at home was cutting the biggest pieces of squash I ever saw in my life and it was way too big for me to cut ... So please stop with these crazy lies for the Hollywood books!!! (sic)"

The '...Baby One More Time' hitmaker - who has Sean, 16, and Jayden, 15, with her ex-husband Kevin Federline - subsequently called her sister "scum" following her recent accusations.

Her post continued: "NOW and only NOW I do know only a scum person would make up such things about someone. I'm actually very confused about you making that up because it's honestly not like you at all!!!! Around the kids???? Jamie Lynn, seriously??? Come on!!! Congrats on introducing your older sister [to] the concept of getting LOW... LOWER... LOWEST... because you win one that one, babe [trophy emoji] !!!! (sic)"

Jamie previously alleged that Britney once locked them both in a room while "grabbing a knife".

Asked why she included the knife allegation in her memoir, she said: "I was scared. That was a moment I had. I also was fearful to really say anything because I didn't want to upset anybody, but I also was so upset that she didn't feel safe."