The Woman in Black actor said that he almost gave up playing the boy wizard after 2004's Prisoner Of Azkaban, as he feared having to dedicate himself to the remainder of the series.
"There was a time after the third film when I thought about quitting," he told Shortlist. "It was only for a second, but I thought, 'If I do the fourth, I'll have to do them all', and that seemed quite daunting.
"If I was going to leave, that would have been the perfect time because it would have given whoever came in to play Harry enough films to establish himself properly. It wouldn't have totally dumped him in the s**t. But then I started thinking, 'What other good parts are there for 15-year-olds? None'."
Despite his Harry Potter nerves, Radcliffe stated that he wouldn't refuse starring in another high-profile franchise such as James Bond.
"I'd like to be in the new one [Skyfall], with Sam Mendes directing," he admitted. "But I don't know if I'd be any good as Bond. I definitely wouldn't want to follow Daniel Craig.
"I'll let someone else have a go first. Erm… who'd be terrible as Bond?"
Radcliffe has said before that he would return to the Harry Potter series, despite admitting to being embarrassed by his performance.
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Watch Daniel Radcliffe in the trailer for The Woman in Black below: