Scarlett Johansson complained about the "rigid diet" she's on when she showed up "very slim" to a London film party Tuesday, says Page Six's source. The starlet does seem streamlined.

The left halves of these pictures are from Tuesday's event. The right halves are from the Met's Costume Institute Gala in May, nearly a year ago.

Perhaps the actress is prepping for a film role. Maybe she's tired of people talking about "The Johanssons." But the sudden weight loss does make one wonder whether Johansson has changed her opinion about America being "obsessed with dieting rather than focusing on eating well, exercising and living a healthy life."

Particularly if one is insane with jealousy at Johansson's frankly elegant new look.