Unbeknownst to many, Britney, Ke$ha, Carly Rae Jepsen, and a cabal of their pop star comrades share a secret weapon: Her name is Bonnie McKee, and she's got an uncanny knack for crafting massive hits. Though she flirted with solo performance, the Seattle-raised songwriter shines behind the scenes, concocting smash singles that offset moody vibes with danceable beats.