Speaking on 'The Late Show With David Letterman' in New York, the British beauty said: "Yes I have tried spirits, we drink at 18 in the UK but I'm actually legal to drink here now, it's worth mentioning. Yes, yes I have. I got very very drunk once in my life as everyone does. Fine I got drunk, I have been drunk - and I'll bow to that!"
Although she admitted to getting drunk, when asked if she had ever peed on the subway, Emma replied: "No it's never gotten that bad - thankfully it's never been that bad."
While Emma is sensible with her drinking, her 'Harry Potter' co-star Daniel Radcliffe recently confessed he became "reliant" on alcohol when he was 18.
The 22-year-old actor - who has now given up drinking - said: "I became so reliant on alcohol to enjoy stuff. There were a few years there when I was just so infatuated with the idea of living some sort of famous person's lifestyle that really isn't suited to me."
'Harry Potter's' Emma Watson scares little children
'Harry Potter's' Daniel Radcliffe has confessed he developed an alcohol problem at 18
Emma Watson feels like a "different person" to the girl in the early 'Harry Potter' films - VIDEOS