Kevin Federline Expresses Concerns About Britney Spears in Exclusive Interview

Kevin Federline gives an exclusive interview to ET's Kevin Frazier ahead of releasing his memoir, 'You Thought You Knew,' out Tuesday, Oct. 21. The father of Britney Spears' now-adult sons, Sean Preston, 20, and Jayden James, 19, opens up about his ex's concerning life after conservatorship, all while sharing untold stories from their time together, including details from the call Britney had with Justin Timberlake on their wedding night.