United Kingdom, Oct. 15 -- Kevin Federline has claimed Britney Spears cheated on him with a female dancer.

The 47-year-old star - who split from the Toxic hitmaker in 2007 after three years of marriage - claimed he found the pop star locking lips with another woman in a hotel room in Amsterdam early in their relationship, leaving him "stunned".

Explaining how he, Britney, dancers and other tour staff had enjoyed a "loose, carefree" night on the town before heading back to the hotel in the early hours of the morning, Kevin told how his then-girlfriend suddenly disappeared and he went looking for her.

In an excerpt from his memoir You Thought You Knew shared by USA Today newspaper, he wrote: "Eventually, I decided to check if everything ...