Britney Spears and Kevin Federline‘s relationship got off to a hot-and-heavy start.

In his upcoming memoir, You Thought You Knew, Federline, 47, recalls Spears, 43, taking him back to her hotel the same night that a mutual friend had set them up.

While Federline was a backup dancer for LFO when the band opened for Spears on her 2000 tour, he never properly met the Princess of Pop until fellow dancer Teresa Espinosa introduced them at Joseph’s nightclub in Hollywood in 2004.

“The moment I sat down, everything else kind of just faded into the background,” he writes. “It was just me and her.”

Federline, who was 26 at the time, admits he was “just thinking about smashing” Spears and had no idea they would go on to marry.

Eventually, Spears invited Federline to join her crew for a late-night swim at the Beverly Hills Hotel, where she “had a bungalow with a private pool and hot tub.”

“Then, while everyone was still swimming, Britney got out of the hot tub, grabbed my arm and led me into the bungalow,” he writes. “Everyone else must have got the message and eventually left. I wasn’t worried about anyone else though.”

“We stumbled toward the bed while I struggled to kick my pants off my ankles,” he remembers. “This. Is. Happening.”

However, Federline stops the anecdote there, telling readers, “Okay. Sorry, calm down, that’s as detailed as I’m going to get on that.”

Federline shares that the evening was “purely physical,” but what started as “one night became two, then stretched into three, the whole time holed up in that bungalow.”

The pair quickly got to know each other, and then Spears invited Federline to join her on the European leg of her Onyx Hotel Tour.

The couple said “I do” later that year. After welcoming sons Sean Preston, 20, and Jayden James, 19, in 2005 and 2006, respectively, their whirlwind marriage ended in divorce in 2007.

Ahead of the Tuesday, October 21, release of You Thought You Knew, Spears publicly slammed Federline for its explosive claims.

“The constant gaslighting from [my] ex-husband is extremely hurtful and exhausting,” she wrote via X on Wednesday, October 15, before calling out his “white lies” that are “going straight to the bank.”

That same day, Us Weekly exclusively interviewed Federline, who insisted, “Money’s not the root of this thing. I feel like, if she has the right to tell her story, why don’t I?”

Indeed, Spears did look back on her ill-fated romance with Federline in her own 2023 bestseller, The Woman in Me, including the night they met.

“In the beginning, my relationship with Kevin was physical,” she wrote, clarifying that it was more about intimacy than “a sexual thing.”

These days, Spears and Federline are no longer on speaking terms, though she has reconciled with her once-estranged children over the past year.

“Rebuilding her relationship with her sons is her biggest priority right now,” a source exclusively told Us in September.

You Thought You Knew is available on Tuesday, October 21, via Listenin, an audio-first platform.