Kevin Federline has voiced deep concern for his ex-wife, Britney Spears, in his forthcoming memoir You Thought You Knew, alleging that the pop star’s mental health has declined and suggesting that her 2021 release from conservatorship may have been premature.

In excerpts published Tuesday (Oct. 14) by The New York Times, Federline writes that he fears Spears’ situation “is racing toward something irreversible.” The former dancer and reality TV personality, who shares two sons with Spears, says he has struggled to watch her recent public behavior without intervention. “It’s become impossible to pretend everything’s OK,” he writes. “From where I sit, the clock is ticking, and we’re getting close to the 11th hour. Something bad is going to happen if things don’t change, and my biggest fear is that our sons will be left holding the pieces.”

Federline and Spears were married in 2004 and finalized their divorce three years later. Their sons, Sean Preston and Jayden James, are now 20 and 19. The boys have lived primarily with their father for much of the past decade and relocated with him to Hawaii in 2023.

In You Thought You Knew, Federline reportedly describes a series of incidents he claims raised alarm about Spears’ behavior toward their children. One passage recounts a moment when the singer allegedly appeared in their bedroom late at night holding a knife. “They 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 writes. “Then she’d turn around and pad off without explanation.”

The accusations have been met with an immediate response from Spears’ camp. A representative for the singer dismissed the account as sensationalism tied to the end of Federline’s financial support. “With news from Kevin’s book breaking, once again he and others are profiting off Britney,” her spokesperson told Billboard. “Sadly it comes after child support has ended with Kevin. All she cares about are her kids, Sean Preston and Jayden James, and their well-being during this sensationalism. She detailed her journey in her memoir The Woman in Me.”

Federline, who has generally avoided lengthy public discussions about his marriage since Spears’ conservatorship ended, writes that his new book is not intended as retaliation but as a warning. “I’ve never, ever, once, been against Britney,” he says in one excerpt. “I’ve only tried to help my sons have an incredible relationship with their mother.”

In a teaser for his upcoming interview with Entertainment Tonight, airing Tuesday evening, Federline expands on that motivation. “I feel like I need to sound the alarm,” he says, describing the memoir as his attempt to confront what he views as an escalating crisis.

He also reflects on how much his ex-wife has changed since their marriage: “When I really reflect on everything that’s happened, my kids do not know the woman that I married. And I’ve spent two decades trying to bridge that gap.”

Since the end of her 13-year conservatorship in 2021, Spears has described the years since as a period of self-discovery and recovery. Her memoir The Woman in Me, published in 2023, chronicled her career, her family’s control over her life, and her attempts to rebuild relationships with her children.

Though her connection with Sean and Jayden has been complicated, Spears celebrated a reunion with her younger son over the 2024 holidays, posting on Instagram that it was “the best Christmas of my life.” “I haven’t seen my boys in two years,” she wrote. “Tears of joy and literally in shock every day, so in love and blessed.”

More recently, the singer has shared photos of herself with Jayden, emphasizing her hope to strengthen family ties after years of public conflict.

Federline’s memoir arrives amid renewed scrutiny of Spears’ private life and the enduring debate surrounding her freedom and health. While his allegations have reignited controversy, his publisher describes the book as a “personal and painful reflection” rather than a tell-all.

You Thought You Knew will be released October 21, with Federline’s televised interview set to air the same evening.