'I Will Never Forget It!': Britney Spears Accuses Mom Lynne Of Once Hitting Her 'So Hard' For Partying Until 4 AM

Britney Spears has taken aim at her mother once again.

The princess of pop alleged in an Instagram post that her mom, Lynne Spears, once slapped her so hard for partying into the early morning hours while she watched the singer's two sons.

"The first time I ever got slapped was the one night Paris [Hilton] and Lindsay [Lohan] dropped me off at my beach house with my babies," Britney claimed, referring to the two sons she shares with ex-husband Kevin Federline: Sean Preston, 17, and Jayden, 16.

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"My mother was watching Jayden and Preston...yes I partied till like 4am and my mother was PISSED !!!! I walked in, she looked at me and hit me so hard that I will never forget it !!!" Britney continued.

According to the "Toxic" songstress, the incident occurred after Kevin "left" her, as two split in 2006 after tying the knot in 2004.

Britney also claimed in her caption of a clip of 2005's Monster-in-Law — in which a young Jane Fonda and Jennifer Lopez get in a disagreement that results in the two repeatedly slapping the other across the face — that she has "never slapped anyone my whole life."

"I WOULD GIVE ANYTHING TO SEE WHAT THAT FEELS LIKE ... JUST SAYING !!!" she wrote. "… GUESS I WILL NEVER KNOW !!!! Stay classy folks !!! This was all 15 years ago … I mean we've all grown up since then !!!"

Britney posted the movie clip with a similar caption sans the altercation with her mom earlier in the day on Monday, October 10, and seemed to add more detail later on.

Britney recounting the alleged altercation comes one week after Lynne issued a public apology in the comments section of one of her eldest daughter's posts and begged the "Gimme More" vocalist to unblock her so they can talk.

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Lynne replied to Britney's post that said a "genuine apology would help give [her] closure" in their years-long family feud.

“I am soooo sorry for your pain! I have been sorry for years!" Britney's estranged mother, 67, commented at the time.

However, Britney made it clear that she wasn't ready to accept Lynne's apology, telling her to "go f**k" herself before reflecting on the abuse she endured during her near-14-year-long conservatorship.