Emma Watson is a Quick-Change Artist

Maybe it's because she got drenched on the red carpet by the soaking rains at the London premiere of Harry Potter and the Half-Blood Prince earlier this week, but actress Emma Watson came prepared with two completely different dresses — and wore them both — for her appearance on The Late Show with David Letterman on Wednesday night.

CHECK OUT BOTH OF EMMA'S LATE SHOW LOOKS IN THE GALLERY!