Possible soon-to-be Playboy centerfold mom Britney Spears was chastised in a nasty public tongue lashing from the lips of the woman she believes is bedding ex-husband Kevin Federline-her estranged mom Lynne Spears!

According to celebrity gossip vet Mike Walker:

Brit was sucking on a cigarette, swilling some coffee, chomping gum and “giggling like a loon” when she exited swanky Kitson on Robertson Blvd. – and suddenly got the grin seared off her kisser when a teenage fan’s fire-breathing momma blasted Ms. Toxic, labeling her a grungy, low-life role model…and a lousy mother!

Lynne is said to have elbowed Brit in the side and shouted:

“Excuse me…but I hope you get your life together, work things out with your mother – then start taking care of your children! Family is the most important thing in the world!”

“You have absolutely NO manners!” reported ‘adoptive’ mom Lynne fumed

“You have dirty habits, and you’re a terrible example for young girls – not to mention your fans…if you still have any!”

“Lady, mind your own f-bomb business…then stormed off down the street,” Britney screamed before turning away.