She's the mad hatter!

Sarah Jessica Parker channeled her quirkiest Carrie Bradshaw — topping off her look with an acorn-and-garden-inspired headpiece from famed British milliner Philip Treacy — at Monday's world premiere of "Sex and the City: The Movie" in London.

The hat came complete with flower, grass and a pair of butterflies. Thankfully, there were no squirrels.

"This is the fashion equivalent of getting a master's at Harvard. Seriously. There is no awkwardness, no discomfort. It's costume-y, but it's costume-y in the most fabulous way," says celebrity stylist Robert Verdi of Parker's headwear.

"Sarah is one of the only people that can make sense of fashion when it's elevated to art," he added. "I think it would look crazier in the U.S. than it does there. I think it looks fabulous."

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