As Radcliffe explained, he was confused himself as to why Yankovic wanted him to play the role. "When I talked to Al for the first time, I was like, 'I'm immensely flattered by the idea that you would pick me to play you, but like, why me?'" the actor told Jimmy Fallon.
The answer goes back to November 2010, when Radcliffe sang satirist Tom Lehrer's novelty song "The Elements," which lists most of the elements of the periodic table, on The Graham Norton Show.
"I sang 'The Elements' next to Colin Farrell and a very bemused Rihanna, who I think was like, 'Who is this kid and why is he singing all of the elements?'" Radcliffe recalled. "And I guess Al saw that and was like, 'This guy maybe gets it.' And so picked me."
How Daniel Radcliffe was cast