Call Kevin Federline what you want; K-Fed, Fed-Ex, even the PopoZ??o pimp; as the former-Mr. Britney Spears, he???s no stranger to mocking nicknames thanks to his infamous popularity in the tabloids. After a whirlwind year in the spotlight (he went from a backup dancer to a celebrity husband with three of his four children being born within 12 months of each other to model to failed rapper), Federline has seemingly turned over a new leaf, as he???s currently the primary custody holder of Sean Preston and Jayden James, his two youngest sons with ex-wife Britney Spears.