It took seven years for Katy Perry to become an “overnight sensation” when “I Kissed a Girl” hit in 2007. Racking up five number-one songs from her album Teenage Dream, Katy’s now an undisputed pop-chart megahit-maker and she’s still under 30. Snakkle looks at how Katheryn Elizabeth Hudson became the Katy Perry depicted in her new movie, Katy Perry: Part of Me.