Kevin Federline has expressed deep concern over the recent behavior of his ex-wife, pop icon Britney Spears, suggesting that her current trajectory might lead to a tragic outcome.

In his upcoming memoir, “You Thought You Knew,” Federline shares his worries, as reported by the New York Times. “The reality is that the situation with Britney seems to be heading toward something that can’t be undone,” he writes.

Federline, who co-parents sons Sean Preston, 20, and Jayden James, 19, with Spears, admits, “It’s become impossible to keep pretending everything is fine.”

He adds, “From my perspective, time is running out. We’re nearing a critical point, and if things don’t change, there could be serious consequences. My greatest concern is that our sons will be left to pick up the pieces.”

The 47-year-old former backup dancer also recounts a troubling incident when his sons expressed fear and reluctance about returning to their mother’s home.

“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,” he claims.

“Then she’d turn around and pad off without explanation,” Federline adds.

The DJ says he has “never, ever, once, been against Britney” and has only tried to help his sons and have a great co-parenting relationship with Spears.

“It’s hard because 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,” he confesses.

Federline, 47, and Spears, 43, tied the knot in September 2004 and welcomed their sons, Sean Preston and Jayden, in September 2005 and 2006, respectively.

The duo got divorced after three years of marriage and spent several years locked in a contentious custody battle that was further complicated by her controversial conservatorship.

In 2023, Federline relocated to Hawaii with his sons and his new wife, Victoria Prince, after she landed a job on the island.

Last month, Page Six exclusively reported that Spears has been refusing help from people as fears about her mental health and living conditions continue to grow.

The Grammy winner’s friends are also reportedly worried that Spears is residing in a “messy mansion” covered in dog poop.

“Her house is a mess. She doesn’t clean up after the dogs, she doesn’t have someone there cleaning every day, and she just isn’t functioning like an adult would function,” a source told the Daily Mail last month.

Meanwhile, a source told Us Weekly that the “Womanizer” songstress has been focused on “healing” with her boys.

Federline’s memoir, “You Thought You Knew,” is set to be released on Oct. 21.