When she donned the hoodie: The music video Obsessed (2009)
Why she did it: To mock Eminem, who she dated in 2001 and sings about in the song. "You're so lame. Oh boy, why you so obsessed with me? Oh finally found a girl that you couldn't impress? Last man on the earth still couldn't get this."
Convincing? She looks like a man, not Eminem. But the transformation is surprising.
Costume feasibility: Uh, grab a baseball hat, a hoodie, some baggy pants and voila? This one's not labor intensive