Kevin Federline is ready to move on from his Britney Spears era. But first: a memoir.

To hear Kevin Federline tell it, he never stood a chance.

It’s been more than 21 years since Federline was first photographed with Britney Spears. It was 2004, and the pop princess was still getting heat over the end of her high-profile romance with Justin Timberlake. The “Oops!… I Did It Again” singer followed that with a blink-and-you-missed-it Las Vegas elopement that her parents made her annul.

Enter K-Fed, a backup dancer for LFO and Pink, and self-styled bad boy, four years Britney’s senior. Faster than you could ask, “Who’s Britney’s new man?” the tabloids told the story for him, leading with the exclusive that he ran off with Spears while his then-girlfriend, Moesha actress Shar Jackson, was six months pregnant with their second child.

To Britney fans, the revelation cast him as an unwelcome leading man in Spears’s next chapter — and, as he later rapped, “America’s Most Hated.”

“From the get-go, I wasn’t introduced to the world in the greatest way,” Federline, now 47, tells Yahoo in a conversation about his new memoir, You Thought You Knew. “I made some poor decisions on that part. From there, me being quiet made everybody feel like they could say whatever they wanted, and I wasn’t going to come back at them.”

And they did. At the height of the brutal mid-2000s tabloid and paparazzi era, “K-Fed” became a punchline. He was branded a gold digger for marrying Spears just months after they met — and for looking way too comfortable in his new $200,000 Ferrari. A deadbeat dad for leaving his pregnant ex. Lazy for not working.

When he did work — on his song “Popozão” or the brief but memorable reality show Britney and Kevin: Chaotic — he was called untalented.

After having two sons and going through a messy, public split in 2006, the narrative got darker. Federline won primary custody of their children with $20K a month in child support payments — and soon after, Spears was placed under a conservatorship that would control her life for the next 13 years.

“Silence didn’t bring peace,” Federline tells us, but he’s hoping the memoir, out Oct. 21, does.

He compares the writing process, for which he admittedly had “a lot of help,” to “a yearlong therapy session.” He tells his side of Federline vs. Spears, but it’s really his life story, warts and all. That means revisiting parts he’s not proud of: impulsive choices, messy relationships, sometimes letting down his children, partying too much and other moments he now sees differently as a man in his 40s, a father of six and a new grandpa.

“I hope this book brings a better perspective to people on who I am,” he says. “There’s a lot in there — being transparent and reflecting on my own doings and my own part in this — that I think will give people a good understanding of who I am and what I went through. I’m finally coming forward and showing people: This is who I’ve been the whole time.”

‘I’ve never been against Britney’

As press for his book has rolled out, media accounts have zeroed in on what he wrote about Spears, which she has issued scathing responses to, and renewed debate — and K-Fed hate — online.

While he has been hit with criticism for opening old wounds, it can’t be overlooked that Spears told her story first in her 2023 bestselling memoir, The Woman in Me. And, yes, he read it.

So, we ask: Is he hoping his book will finally close the chapter — now that both have had their say — or is it just going to keep the back-and-forth going, 20 years on?

“I’ve never been against Britney,” he replies. “I only want good things for her. That’s the type of person I am. I want my children to have a great relationship with her. The back-and-forth, I feel, is more of a play from the media. Like I said, I’ve never been against her.”

In recent years, there’s been a growing reexamination of how the media machine treated celebrities in the 2000s. Is Federline hoping his memoir might win him some of that forgiveness?

“I mean, I don’t know,” he says. “I’m trying to go in with no expectations, because you never know how people are going to react. I think it’s always going to be a 50/50 thing. That’s just kind of how society is split down the middle right now anyway on everything.”

He says he just wants to “gain some support for my children”— Sean Preston, 20, who goes by his middle name, and Jayden, 19 — and have the “public get behind my sons.” By all accounts, they have a fractured relationship with their mother.

“They’re the ones that have to carry this on,” Federline says. “They’re the ones who are adults now and are going to be living this life.”

In the book, he writes that while the #FreeBritney movement led to Spears’s conservatorship ending, he’s still fearful for her well-being. What does he hope to accomplish by detailing his worries in the book?

“It would be great if everybody could see what the common ground is here,” he tells Yahoo. “I feel like so much finger-pointing has gone on. They vilified her family. Me. So many people in this. If you really sit back and look, it’s like: Everybody wants her to be happy and healthy. I want her around for my kids. I want her around for as long as possible in their lives. So the goal here is pretty much the same.”

‘Money is not at the root of this’

The lingering public perception of Federline is that he has lived off Spears’s dime, using child support from her to pay for all six of his children with three women (including his two youngest with wife Victoria Prince). His book doesn’t shy away from dollars and cents.

Federline gets specific: He writes that the alimony he received when divorcing Spears was $20,000 a month for one year. His child support payments, which have now ended, were an additional $20,000 a month — much of which went to security, a nanny and living expenses, he says. He used his money from Chaotic to pay for part of their Malibu house, an investment netted him $1 million when he and Spears sold it. He also spells out how much he got for various gigs, Including $1 million for the Super Bowl commercial, nearly $500,000 for Celebrity Fit Club and $100,000 for a club appearance.

But he isn’t laying it all out there to silence his detractors, he insists.

“I don’t think I did that for that purpose,” he says. “I did that because when you bring celebrity into the situation, especially in my situation, I was nowhere near her tax bracket. I felt it was important to give a piece of that.”

Besides, he adds, “the child support [amounts and other financial details] had already been printed. It’s already things that have been talked about. I thought it was important to not only discuss some of the financial stuff … [but] to touch on almost every single thing people have been concerned with. All of these things have been [following me] for 20-plus years.”

Of course, there’s a question hanging over all of this: Did the end of the child support have anything to do with him deciding to come out with a book now?

“No,” Federline says. “That’s the other thing: Money is not the root of this. This is not about [that]. It is about me finally coming forward and telling my story, because I’ve stayed quiet for the sake of my family and waited until my kids were old enough to get behind it. It’s something that my whole family is on board with, and that’s what it’s about. It’s about really telling my truth.”

Federline emphasizes the importance of family ties and staying connected to Spears’s relatives. While he hasn’t spoken to his ex-wife in years, he says he is still in touch with members of the Spears family. Preston and Jayden still see their grandparents Jamie and Lynne, and their aunt Jamie Lynn.

“I do speak to the family,” he says. “I have this whole time. I’ve always believed in keeping an open line of communication and [access] to the kids through all of this. Everybody deserves to have their time, and I want my kids to know all of their family members. That was important to me.”

In his book are what Federline claims are two direct messages Jamie Lynn sent to his wife that praised the couple parenting of her nephews. Did he get Jamie Lynn’s permission to include them?

“I don’t want to comment on that,” he replies, choosing to leave readers to draw their own conclusions. “I really want to save that for people to read in the book because I feel it’s a very important piece.”

A fresh start for K-Fed

In 2023, Federline left Hollywood for Hawaii, where his wife of 12 years is a beach volleyball coach at her alma mater, the University of Hawaii. He teases having a “few projects in the works” himself after wrapping up his book tour.

“This place is special,” he says of life in his new home. “It’s brought peace. It’s gotten me back to the center and able to move forward and navigate my own life, raise my children who aren’t adults and do that in the best possible way.”

Preston and Jayden have officially flown the coop. He says they — as well as Kori and Kaleb, his children with Jackson — “know it’s a place they can always come back to and visit. It became a perfect situation. … I’m so happy that we finally made the move.”

Another milestone moment: Federline recently became a “proud” grandfather when Kaleb, 21, welcomed a child of his own.

“What I’ve realized is: You blink and that time is over,” he says of parenting. “So the one thing that I am grateful for is the fact that I’ve been able to spend so much of that time with my children. Because it goes by so fast. And I’m grateful to my exes, Shar and Britney, for giving me four priceless pieces of my life.”

And now? “I’m ready for the next chapter,” he says. “I’m ready to move on from all this and finally be at peace.”