LOS ANGELES (Reuters) - Daniel Radcliffe admitted he was drunk while filming some scenes for the "Harry Potter" movies during a period in his life where he was drinking "nightly," the young star said in an interview.

"I have a very addictive personality. It was a problem. People with problems like that are very adept at hiding it. It was bad. I don't want to go into details, but I drank a lot and it was daily - I mean nightly," Radcliffe said to British celebrity news magazine Heat earlier this week.

"I can honestly say I never drank at work on 'Harry Potter.' I went into work still drunk, but I never drank at work. I can point to many scenes where I'm just gone. Dead behind the eyes," the 22-year-old actor said.

The young British star, who was propelled to fame at 11-years-old after being cast to play boy wizard Harry Potter in the movies based on J.K. Rowling's best-selling novels, discussed his "very busy personality" and also talked about his production-assistant girlfriend, who he said was "a wonderful, wonderful girl, who's far too good for me."

"I can also be quite insecure. A lot of actors have self-doubt. I live under that the whole time, and it's how I function best. I think she puts up with a lot; she says she doesn't," said Radcliffe.

The "Harry Potter" star, who has received critical praise for his theater work in the Broadway and West End productions "Equus" and "How to Succeed in Business Without Really Trying,"

is currently on the promotional rounds for his film, "The Woman in Black," out in U.S. theaters on Friday.

(Reporting By Piya Sinha-Roy; Editing by Bob Tourtellotte)