The 30-year-old star became JK Rowling’s boy wizard aged 11 and went on to film eight movies during his teenage years. Asked how he dealt with the attention, he told BBC Radio 4’s Desert Island Discs: “I think badly at first. If I went out and got drunk I’d suddenly be aware of there being interest in that because it’s like, ‘Oh, Harry Potter’s getting drunk in the bar’.
“And those are the moments where I started going, ‘Oh, that doesn’t feel good. I don’t like how I’m being looked at’. The way of dealing with that is just to drink more or get more drunk – so I did a lot of that for a few years.”
Daniel doesn’t know whether the drinking was down to his nature or because of the circumstances he found himself in.
He added: “Is this thing the way it is because it is in you to be that way? Or was it because you got famous and were in this crazy situation? I’ll never know.
“But I definitely think a lot of drinking that happened towards the end of Potter and for a bit after it finished was panic and not knowing what to do next. And not being comfortable enough in who I was to remain sober.”
Daniel stopped drinking in 2010 and moved into other TV, film work and daring theatre roles.
He also explained that he feels the need to prove that he is a nice guy and establish he is not “awful” when he meets new people.
Daniel, who appeared in the movies with Emma Watson and Rupert Grint, praised his family and the others on set for ensuring they all grew up well.
He said: “A huge amount does come down to my parents and to other people, who were able to help me at key moments.”
Daniel chose tunes Bring Me Sunshine by Morecambe and Wise, Joanna Newsom’s Emily and Attaboy by Yo-Yo Ma, Chris Thile and Edgar Meyer. He would also take a pen and paper, and the Norton Anthology of Poetry.
● Desert Island Discs, BBC Radio 4, today, 11.15am