Credit: Steve Granitz/

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.

"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."

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.

"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.