Emma Watson laughed off an accidental red carpet wardrobe malfunction during an appearance on last night's Late Show With David Letterman.

The actress inadvertently flashed her underwear at Tuesday's London Harry Potter premiere while adjusting her floor-length vintage Ozzie Clark dress in the pouring rain.

See more photos of stars in their skivvies.

"This was a small wardrobe malfunction that happens," Watson, 19, giggled to Letterman while holding her head in her hands. "I actually don't remember it happening."

Check put pics of stars goofing off.

There was one saving grace though. "At least I'm wearing underwear!" she joked as the audience laughed.

See how different teen stars looked two years ago.

Watson -- who is currently shooting the last book in the Potter series,Deathly Hallows -- declared: "I'm still learning. I'm still learning!" Harry Potter and the Half Blood Prince hits theaters July 15.

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