This Bad Teacher deserves an A+.

Cameron Diaz hit up the 84th Annual Academy Awards in a strapless Gucci gown that showed off her famously fit figure. The actress, 39, got ready for the star-studded event with her celeb BFF Gwyneth Paltrow, also 39.

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"This isn't one of those things you can just throw together overnight," Diaz told ABC's Tim Gunn of her look. "It's a process. I just try to see what's out there gown-wise and this year there were so many beautiful gowns."

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The actress, who split with baseball player Alex Rodriguez last fall, admitted that "the train is a little heavy, but it's so masterfully crafted." She accessorized with Tiffany & Co. jewels, worth almost $1 million.

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"These dresses are works of artisans, and the way that they fit and the way they hold onto [your] body, you know who you're dealing with when you put it on your body," Diaz added.

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