Kevin Federline Talks Fears for Britney Spears, Denies Book Is Money Grab (Exclusive)

It’s one of the most talked-about books of the year, delivering one jaw-dropping headline after another about legendary pop star Britney Spears!

“Extra’s” Terri Seymour spoke with Kevin Federline from his home in Hawaii about his new memoir “You Thought You Knew” and why he’s “sounding the alarm” about concerns for his ex-wife Britney.

Kevin opened up on why he chose to release the memoir now, saying, “I feel like over the last two decades, my story has been told through a different lens and I felt it was important for me to finally come out and tell my story.”

Referencing their sons Jayden James and Sean Preston, he elaborated, “Right now my kids are old enough to understand and approve what I’m doing. I don’t want my kids living their lives and having to explain who I am. I say that in the book — I don’t want them talking about things that they didn’t live through or can’t remember.”

He went on, “Coming out and speaking your truth, especially after you’ve had so much [time] to reflect on it with compassion and understanding, I think it’s important because no matter how loud it is on the outside, everyone deserves to have a voice.”

In the book, Kevin says his relationship with Britney began with a hookup at the Beverly Hills Hotel after a chance meeting at an L.A. hot spot.

The newlyweds told Ellen DeGeneres their marriage proposal wasn't a typical one since Britney popped the question, but that sweet relationship would soon turn sour.

In his book, out Oct. 21, Kevin reveals never-before-heard stories of an international pop star on a serious mental health decline.

Britney has hit back on social media, slamming Kevin for “gaslighting” and saying she’s “demoralized” by the situation with their sons.

As for why he felt the need to speak out, Kevin said, “I mean, it’s exactly what it is. Every day I wake up fearing my children will possibly have to deal with the unimaginable.”

Federline shares some disturbing stories in the book, even claiming that their kids woke up once to Britney standing in the doorway with a knife in her hand.

Kevin recalled, “For me, as a parent, I was absolutely terrified, shocked that they had to go through something like that. I didn’t find any of this stuff out until after they stopped seeing her and really after the conservatorship ended. That's when they started telling me some of the stories that had happened. Even that is alarming. These instances are part of the reason why I felt the need to come out and sound the alarm.”

While they were married, Federline also sounded the alarm with Spears after he claims he caught her doing cocaine while she was breastfeeding their kids.

Kevin said, “It definitely raised some red flags for me.”

In his book, Federline says he begged her not to go home and breastfeed.

Kevin told Terri, “It became a huge ordeal and a few days later, she wound up filing for divorce.”

Another story he shares in the book is about when Sean Preston went to Europe and Britney called him. Kevin described the erratic call from Britney to her oldest son as the breaking point.

Federline shared, “He called me and told me, you know, that his mom wished that all of us were dead, and this just came out of nowhere… It’s interesting because he took it better than I did.”

Today, Britney still has a large presence on social media. She has been turning heads with some of her posts, like one where she’s dancing with knives.

Federline weighed in on her social media, admitting that he was “scared” and “worried.”

He went on, “I feel like I’m sending out a cry for help, right? For anyone that’s ever cared about her and has been captivated by her, now is the time because I want her to be around for our kids for years and years and years.”

Britney lashed back on social media, begging for her boys to be part of her life, saying, “They need to take responsibility for themselves.”

Kevin opened up about his sons’ relationship with their mom today, saying, “I mean, it’s a fluid situation. I know they talk. My boys love their mom.”

In the book, Kevin also reveals he received 40 grand a month in support from Britney, which stopped when their youngest, Jayden, turned 18.

Britney's team claims Kevin’s profiting off of her...  and she threw a jab at him in her post, saying, “Those white lies in that book, they are going straight to the bank.”