Inside Britney Spears and Kevin Federline’s all-out war of words

The knives are out.

Britney Spears and Kevin Federline are in an all-out war after the father of her two kids has unearthed sharp claims in his memoir, “You Thought You Knew” (out Tuesday) — alleging his ex-wife was physically and verbally violent with their sons and even used cocaine while breast-feeding.

Federline, 47, writes that he walked into a dressing room at his album-release party in 2006 to find “Britney and [a] young starlet friend snorting a fat line of coke off the table …They didn’t even try to hide it.”

At the time, their son Sean Preston (who goes by his middle name) was 1 year old and Jayden James was 1 month old.

“Please don’t go home and breastfeed the kids like this. Call your mom or someone. We need to get formula. You can’t do this,” Federline recalls saying.

When his wife allegedly threw a drink at him, he writes, “That was the proverbial final straw, the breast-feeding thing. Her reaction. That’s what ended us.”

Page Six has reached out to representatives for Federline and Spears.

The book also alleges that Spears once punched Preston in the face when he was 10 or 11 years old.

Another time, Federline alleges, the boys came home from a visit with their mother sporting bleached hair.

“Not just streaked or lightly done. It was bleached down to their scalps.Their skin was burned,” he writes. “I had to shave their heads, and their scalps looked like leopard print from their chemical burns.”

According to the book, when visiting Spears, the young boys “would awaken sometimes at night to find her standing silently in the doorway, watching them sleep — ’Oh, you’re awake?’ — with a knife in her hand.”

Federline claims that other harrowing incidents came to light later.

“Then there were the stories the boys shared as they got older,” he writes. “Preston once told me she had punched him in the face.

After the former dancer moved his family — including current wife Victoria and their young daughters, Peyton and Jordan, along with Preston, now 19, and Jayden, 18 — in 2023, the boys stopped seeing Spears.

When the singer told Preston on a phone call that she blamed family members, for her ongoing problems, “Preston, to his credit, confronted her. He called out her lies and refused to accept her narrative. Her response was chilling: she told him she wished he, his brother, and me were all dead,” Federline writes. 

“How could a mother say that to her son? Preston, having dealt with her vitriol for years, took it better than I did … Trauma like that left scars, ones I fear they’ll carry for the rest of their lives,” he continues.

The exposure of all these toxic details has prompted the singer to fight back in public — calling out her ex Wednesday for “constant gaslighting” and dismissing the book as “white lies” that are “extremely hurtful and exhausting.”

“I 100 percent beg to differ the way he is literally attacking me . . . why is HE SO ANGRY . . . and what’s scary is he’s convincing,” Spears wrote on X Thursday. “If you really love someone then you don’t help them by humiliating them.”

Federline, meanwhile, told “Entertainment Tonight” this week: “I just wish that [she] would get help. I’m not going to just expose her personal life. But it’s 10 times worse than anything that I’ve said in my book.”

In the book, Federline, who grew up in Fresno, Calif., details his rise from being a back-up dancer for the boy band LFO to the husband of one of the biggest pop stars in the world.

The two met in the summer of 2004 at Hollywood nightclub Joseph’s and their courtship quickly became a media circus because Federline’s ex-girlfriend Shar Jackson was pregnant with his second child.   

Spears and Federline married three months after meeting and the singer was pregnant with Preston the next year.

But things were tumultuous. During one fight, Federline claims, Spears threw a cocktail in his face. He learned that she had filed for divorce, after three years of marriage, from a TV report — leading to a vicious custody battle.

This was around the time that Spears had a public breakdown, notoriously shaved her head and attacked a paparazzo’s car with an umbrella, actions she has since blamed on postpartum depression and grief from being apart from her sons.

“With my head shaved, everyone was scared of me, even my mom,” Spears writes in “The Woman in Me,” her 2023 memoir. “Flailing those weeks without my children, I lost it, over and over again. I didn’t even really know how to take care of myself.”

It was one of the incidents that led to her being put into a strict 13-year conservatorship in which, Spears has said, she was not allowed to drive, get married or have more children.

The singer’s team said in a statement this week, “With news from Kevin’s book breaking, once again he and others are profiting off her … “

While one source defended Federline to Page Six as a good father, they also said “there’s zero grace given to [Spears] in this whole situation.”

The source said the tell-all is a paycheck for the father of six, who is not known to currently have a job and who was awarded alimony of $20,000 a month for 13 months — half the duration of his marriage to Spears, according to Federline’s book.

Spears also paid $20,000 in child support until her sons were 18.

“People love to assume that I was just coasting off her money, but that couldn’t be further from the truth. I wasn’t some bum just sitting around waiting for a check … My Super Bowl commercial alone paid almost a million dollars for just three days’ work,” Federline writes of the 2007 ad for Nationwide.

Around that time, he says, he was also getting paid $100,000 for paid appearances at clubs in Vegas and Miami. ” At my peak, I was making $300,000 to over half a million a year,” he writes, while admitting: “that cash spent fast.”

His wife Victoria has worked as a special education teacher.

“Kevin is a really nice guy who was thrust into a weird situation — he’s a very simple guy whose whole public life is defined by a relationship he was in,” the source told Page Six. “Kevin’s head and heart seemed to be in the right place.”

In the book, Federline claims his intention for penning the memoir is to “sound the alarm” about Spears’ worrisome behavior.

Since her conservatorship was lifted in 2021, Britney has regained control over her life and full control of her fortune, estimated to be between $40 million and $60 million.

But fans and observers have expressed concern over the singer’s presence on social media — including videos that show her dancing with knives, looking disheveled and making bizarre statements. In one recent video posted to Instagram, dog excrement was visible on the floor of her home.

Writes Federline: “Something bad is going to happen if things don’t change.”  

He even calls on members of the #FreeBritney movement, which tirelessly drew attention to her conservatorship and showed the singer support throughout her court battles, to reorganize as “Save Britney.”

“What does he want us to do? Hire a psychiatrist and send one to Britney’s door?” Pilar Vigneaux, who helped organize the #FreeBritney movement, told Page Six.

“How can we help Britney if everything is redacted?” she added of the singer’s post-conservatorship care plan.

“He’s part of the problem,” Vigneaux alleged of Federline. “One of the crucial parts of the conservatorship was Kevin’s involvement in it. They used the children as bait for Britney to work. They negotiated with Kevin for him to have full custody of the kids and to use the kids to force Britney to work: ‘If you want to see your kids you got to do this show. If you want to see your kids you have to do this album.’

As for current concern about Spears’ mental state, Vigneaux pointed to a trip to Mexico Spears took this past spring and documented on Instagram. “If she was really in such a horrible state and unstable she would have been doing crazy things in Cabo…the Mexican press would have definitely said something about it.”

At the time, though, TMZ did report that Spears was “difficult” and allegedly had to be told by flight attendants to extinguish a cigarette while indulging in a few alcoholic drinks on a chartered plane from Cabo San Lucas, Mexico, to Los Angeles.

Vigneaux also feels that Preston and Jayden, despite the claims in Federline’s book, owe it to their mom to help her if she needs it.

 “If I were her kid … I would try to help her,” Vigneaux said, admitting: “She’ll never be the Britney she once was. She was 27 when her life was stolen from her. You  could never recover from that.”