The 'Fantastic Four' star revealed her modesty in a sheer black undergarment when she took off her long-sleeved jacket accidentally, reported E! online.
But the 32-year-old star, who was more formally dressed when she attended the Met Gala last night, looked stunning in a leather dress by Tory Burch with a cut-out around the bust.
The 32-year-old actress also attended a separate event to promote her book, 'The Honest Life'.