Emma Watson
Cast member Watson arrives for premiere of the film "Harry Potter and the Deathly Hallows: Part 2" in New York. Reuters

Emma Watson was tightlipped about Harry Potter co-star, Danielle Radcliffe's drinking but copped to drinking herself.

To be honest, it's really not something I genuinely know much about, Watson said. He is the one to talk about it.

During an interview with late-night CBS funnyman David Letterman, Watson admitted to being very, very drunk once, before bowing proudly.