Kevin Federline claims Britney Spears cheated on him with female backup dancer in bombshell memoir

One, two, three.

Kevin Federline claims Britney Spears cheated on him with a female backup dancer while they were dating.

In an excerpt of his upcoming memoir, “You Thought You Knew,” obtained by Us Weekly, the DJ recalls a specific night out with his now-ex in Amsterdam in 2004. The two were joined by Spears’ Onyx Hotel Tour crew, including Teresa Espinosa, who introduced Federline to the singer just one month prior.

After returning to their hotel room, Spears allegedly told Federline she would be right back.

“As time passed, I began to wonder what was taking so long,” he writes in his book. “I was thinking maybe she was catching up with someone or handling something tour-related.”

But, as more time passed, Federline went to investigate where his then-girlfriend was.

“As I passed one of the rooms, I glanced inside — and froze. There she was,” he claims. “Theresa [sic] was sitting on the edge of the bed. Britney stood between her legs, hands on her face and they were f–king going at it. Full-on making out.”

Spears and Espinosa allegedly saw Federline before he walked back to his hotel room to pack his bags.

“I just wanted out,” the 47-year-old writes, noting that he let the “Toxic” singer know that he was leaving her and the country.

“She started apologizing, explaining, promising it would never happen again,” he alleges in the excerpt. “She told me she didn’t realize how serious I was about us, that she was overwhelmed and it had been a mistake.”

He claims he told her that he “wasn’t interested in a relationship that involved more than two people” before giving her another chance.

“Those weeks in Europe, navigating that emotional minefield together, laid the foundation of our relationship,” he writes.

“They tested us, changed us and ultimately brought us closer together. It was during this time that I began to realize the depth of my feelings. And while the road ahead was anything but certain, I knew one thing for sure: I was falling in love with Britney.”

K-Fed and Spears, now 43, met in April 2004 before he joined her in Amsterdam for the May 24 show.

Despite the alleged bump on the road, the two went on to get married in September 2004. They then welcomed two kids, sons Sean Preston and Jayden James, in September 2005 and September 2006, respectively.

However, two months after their second child was born, the music legend filed for divorce, citing irreconcilable differences. Since then, the two have had a contentious relationship, which has led to Sean and Jayden becoming estranged from their mom.

Amid Spears’ recent reconciliation with their children, Federline announced he was releasing a memoir, which focuses heavily on his short stint in the limelight as the pop star’s husband.

In other excerpts highlighted ahead of the Oct. 21 release, the dad of two claimed his sons refused to see Spears because they were scared of her.

“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 alleges in the book.

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

He goes on to express concern that something “bad” would happen to their children if he didn’t step in.

“The truth is, this situation with Britney feels like it’s racing toward something irreversible. It’s become impossible to pretend everything’s OK,” he adds.

“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.”

In his book, he goes on to claim that Spears’ “erratic behavior” is far worse than fans can imagine following the termination of her conservatorship in 2021. He also alleges he caught her on the phone with ex Justin Timberlake just one day before their wedding.

“With news from Kevin’s book breaking, once again, he and others are profiting off her and sadly it comes after child support has ended with Kevin,” a rep for Spears told Page Six in a statement.

“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.”

Page Six has also reached out to Espinosa for comment.