Article continues below advertisementBritney Spears fans aren't holding back after Kevin Federline dropped news of his upcoming memoir.The former backup dancer, who was married to the pop icon from 2004 to 2007, revealed on Wednesday, August 6, via a press release that he's releasing a tell-all book titled You Thought You Knew. According to the announcement, the memoir will cover his "highly publicized marriage" with Spears in an "extremely intimate and transparent" way.Article continues below advertisementSource: MEGABritney Spears fans quickly shut down Kevin Federline's new book.