She displayed a little more than she planned to at the world premiere of the latest Harry Potter film in London this week.
But Emma Watson has managed to make light of the wardrobe error which revealed her knickers to a crowd of thousands.
She laughed off the incident on U.S. television, saying: 'At least I was wearing underwear.'
Keeping her dress firmly in place: Emma Watson in New York yesterday after an interview on the David Letterman Show in which she talked about her 'wardrobe malfunction' at the Harry Potter premiere in London on Tuesday
A model of decorum: The actress was determined not to repeat her faux pas
He produced a picture of her adjusting the bottom half of her free-flowing vintage 1970s Ossie Clark dress - and inadvertently putting her knickers on display.
'Tell us what's going on here,' said a deadpan Letterman as he put a copy of the picture on his desk.
Miss Watson giggled and held her head in her hands as she replied: 'This was a small wardrobe malfunction that happens.
Look away now: Letterman shows Emma Watson the photo of her adjusting her dress and inadvertently putting her underwear on show
It could have been worse: The actress, who plays Hermione Granger in the Potter films, was red faced, but said: 'At least I'm wearing underwear'
Oh well: The teenage beauty said she was 'still learning' about red carpet etiquette
The actress, who plays Hermione Granger in the Potter films, appeared on the show to promote Harry Potter and the Half-Blood Prince, which is released in cinemas on July 15. It is the sixth film in the hugely successful series.
Miss Watson could be spending a lot more time in the U.S. in the future.
In a recent interview she revealed that she was interested in going to university in the country.
She said she had considered taking up a place at Cambridge after getting straight As in her A Levels, but was put off because of the interest her going there would generate.
'Cambridge is so high profile', she said. 'I definitely am attracted to [going to study] in the States for that reason.'
Hello America: The star arrived for the interview in a black-spotted dress and brogues before changing into her other outfit
