Article continues below advertisementBritney Spears' ex-husband Sam Asghari defended her with a shady comment about Kevin Federline's upcoming memoir entitled You Thought You Knew."He was a professional father," Asghari quipped to a news outlet. "So it would be the first book that would tell you how to be a professional father."The Traitors star's sarcastic dig was subtle - but direct, as Federline described his memoir as a story on his experience becoming a father to six children.