"It was bad. I don't want to go into details, but I drank a lot and it was daily - I mean nightly," Radcliffe told British celebrity news magazine Heat 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 the age of 11 after being cast to play boy wizard Harry Potter in the movies based on JK 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".
The star has received critical praise for his theatre work in the Broadway and West End productions Equus and How to Succeed in Business Without Really Trying.
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