This week sees the release of the so-wild-it-must-be true documentary The Imposter, which tells the tale of Frédéric Bourdin, an international master of disguise who, in the 1990s, impersonated a missing Texas boy, one of countless identities the chameleonic subject assumed. Bourdin's story may be all too real, but his is one of many impostor tales we've seen committed to film, as so much suspense rests on characters not being who they seem. In the cases of stars in drag, stars undercover, and stars on the run, viewers are usually in on the incognito secret. Sometimes, though, the ruse is so convincing that everyone is fooled, swept up by the yank of the proverbial rug.
Greta Garbo in Mata Hari (1931). In the risqué role that sexed up her most commercially successful film, Greta Garbo is all sparkle and sizzle, forever popularizing her title character as history's foremost femme fatale. Mata Hari may completely look the part of a dancing courtesan, who masters the come-hither stare and handily seduces Ramon Navarro's Lt. Rosanoff, but she's actually a trained German spy, whose World War I espionage ultimately led to her execution.