SAN DIEGO -- Ian McKellan says there "clearly is" a lighter, almost musical tone to Peter Jackson's adaptation of "The Hobbit" movie, compared to the "Lord of the Rings" story.

The latter is "a long novel about saving the world... The stakes in 'The Hobbit'... they're going on an adventure. They're trying to get some money out of the mountain. It's a story parents tell their kids at bedtime," McKellan said in his interview with HitFix at the 2012 San Diego Comic-Con.

McKellan will be reprising his role as beloved Gandalf, only this time surrounded by more comedians and comic actors. Though, he concedes there will be some darkness.

And then he sings... darkness.

Check out the full video interview above.

"The Hobbit: An Unexpected Adventure" arrives in December, while "The Hobbit: There and Back Again" -- which was shot back to back with the first movie -- will arrive late next year.