Emma Watson laughed off an accidental red carpet wardrobe malfunction during an appearance on last night’s Late Show With David Letterman, usmagazine.com reports.

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.

“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.”

There was one saving grace though. “At least I’m wearing underwear!” she joked.