Olsen, 25, was ultra-revealing in the navy blue Elie Saab gown.
The lacy skirt, with a train trailing behind her, exposed her legs up to her hips. Only a matching navy blue panties protected her modesty.
Up top, the strapless dress clung to her chest while her sexy shoulders were bare. Lizzy wore her below-the-shoulder hair straight and parted in the middle.
She accessorized with Louboutin pumps, Piaget jewelry and a Ferragamo bag.
Fiance Boyd Holbrook clutched her tightly at one point, perhaps trying to shield her modesty.
She was also joined by co-stars Bryan Cranston and Aaron Taylor-Johnson, who posed on the red carpet with his wife.
“I didn’t really know what a Godzilla film is; I had never seen one before. But I signed on after talking to Gareth [Edwards], who told me it is the best monster movie ever made,” she told reporters on the red carpet.
This film is scheduled to be released in North America this Friday, May 16. The original film was made in 1954, marking its 60th anniversary this year.
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