Britney Spears Will ‘Come Out Swinging’ If Ex Kevin Federline Goes Too Far in New Memoir

Kevin Federline is ripping the lid off his stormy marriage to Britney Spears in a bombshell memoir titled You Thought You Knew, and insiders say the fragile pop princess is panic-stricken and vowing to strike back in revenge if her ex publicly humiliates her.

The 47-year-old DJ and former backup dancer’s book launches Oct. 21, and is being plugged as a memoir of “fame, fatherhood and the private cost of public life — from one of pop culture’s most misunderstood figures.”

Kevin, who’s had custody of the former couple’s two sons, Sean, 19, and Jayden, 18, since 2008, when Britney flipped out and was placed in a 13-year, court-ordered conservatorship, writes in a press release: “I achieved my biggest dreams, dealt with crushing heartbreak and endured constant ridicule, all while becoming the father my children needed as they experienced nonstop emotional turbulence. If you’ve ever had questions, you’ll find answers here.”

Meanwhile, “Britney is beside herself over this tell-all,” an insider reveals. “She knew it was in the works but never thought he’d go through with it or that he could actually write, being a high school dropout.”

“If he decides to get too personal or twist things, she’s ready to come out swinging with her own version of events.”

The 43-year-old “Toxic” songbird, who was married to Kevin from 2004 to 2007, is now reportedly frantic to get her paws on the book early so she can “assess the damage.”

The insider adds, “She’s desperate to get a copy to see exactly what he’s saying. She’s convinced it’s not going to be pretty. Kevin’s been teasing that he’s finally telling his side of the story about what it was like being married to her, and that’s set off every alarm bell.”

Britney published her bestselling memoir, The Woman in Me, in October 2023, and “was fairly restrained when she wrote about Kevin,” says the insider.

The singer’s die-hard fans charge that Kevin’s book is to grab bucks now that she no longer pays child support for her grown sons.

“Guess he’s trying to fill the gap in his bank account,” one fan writes on Reddit. Another slams: “Get a job, leave her alone.”

Adds the insider: “Britney feels like after everything she’s been through, the last thing she needs is her ex dredging up the past for profit.”