Article continues below advertisementKevin Federline Detailed His First Hookup With Britney SpearsSource: MEGAKevin Federline looked back at his marriage to Britney Spears in his memoir.Kevin Federline has no problem spilling all the secrets he has been holding onto in his memoir, You Thought You Knew.In his first-ever tome, out on October 21, Federline has chronicled every aspect of his relationship with Britney Spears - including the steamy details of their first encounter.