Kevin Federline has claimed Britney Spears called ex-boyfriend Justin Timberlake the night before her wedding.

In an interview for Entertainment Tonight on Tuesday, the former backup dancer recounted how he discovered the pop star speaking on the phone with Justin and seemingly giving him her "final piece" shortly before tying the knot in September 2004.

Britney and the then-NSYNC member dated from early 1999 until March 2002.

"I was like, 'What's wrong?'" Kevin remembered asking Britney. "I thought she was talking to her mom on the phone or something, and maybe she was having doubts. And she told me she was on the phone with Justin."

Kevin then went on to describe how he reassured the Toxic hitmaker that they didn't have to rush down the aisle.

"I just kind of stepped back like, 'Did I just hear you right? What the hell is going on?' And I immediately was, 'OK, we don't have to do this.' I didn't care if we got married or not," the 47-year-old continued. "And she told me no and really was like, 'I just wanted to make sure that everything is done. I want to make sure that I say my final piece.' I'm like, 'Damn. On the night before our wedding, this is what you decide to do?'"

Kevin noted that he took the interaction with a "grain of salt" at the time and pondered whether Britney was simply "closing a chapter of her life".

"I was super young. I was so madly in love at that moment," the father-of-six recalled. "I couldn't imagine what it was like to be her, I couldn't imagine what it was like to be Justin in those moments, because they were super young. You're talking teenagers that had to go through this globally, and I know that they really cared about each other back then."

Representatives for Britney and Justin have not yet responded to Kevin's claims.

But in the lead-up to the release of the DJ's memoir, You Thought You Knew, on 21 October, a spokesperson for the Princess of Pop insisted she had detailed her journey in her 2023 book, The Woman in Me.

"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," they stated. "All she cares about are her kids, Sean Preston and Jayden James, and their wellbeing during this sensationalism."

Kevin and Britney were married from 2004 to 2007, and share sons Sean Preston, 20, and Jayden James, 19.