The actor was just 11 years old when he was cast as the title character in JK Rowling's wizarding franchise, which wrapped with eighth movie Harry Potter and the Deathly Hallows Part Two last year.
During an appearance on The Tonight Show with Jay Leno, he said: "I cringe very, very hard [when I watch them], particularly the early films. I look like a little frog boy. Chubby and massive eyes on a tiny little head. It's not fun to watch."
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Radcliffe also spoke in the interview about his recent guest-hosting stint on Saturday Night Live, describing it as an "amazing" and "exhilarating" experience.
"It's a whirlwind week and you blink and it's done," he said. "I love that terror that surges through your body before you go on. It was amazing and I had a blast."
As for his favourite sketch, he replied: "Absolutely the Casey Anthony dog [sketch]. I played her dog... When I first read it I was like, 'I don't know how to play that and what do I do? Should I be terrified or what?' Then I saw the wig and how cute it all looked and thought I should just be really angry and furious."
Watch Daniel Radcliffe (and his SNL sketch) on The Tonight Show below:
Radcliffe was on The Tonight Show to promote his upcoming movie The Woman In Black, an adaptation of the Susan Hill novel in which he plays the lead role of lawyer Arthur Kipps.
He recently said that he knew some viewers might struggle to accept his transition from Harry Potter to another genre, saying: "People have seen me in a schoolboy outfit, so it's a little bit of a leap for them to look at me as something else."
"My godson played as my son in the film," he added. "I asked for him to be auditioned. I thought seeing me as a boy and then father would weird people out. I wanted to make sure that the relationship was right and the chemistry was right between me and my son and it is. It really comes across that we know each other."
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