Maybe the inherent goofiness of “School of Rock” (which is in previews, and opens Dec. 6) is just what he needed to shed his self-consciousness and reconnect with the music of crazy trains and purple haze.

As Mr. Lloyd Webber said of the $16 million show: “I haven’t written a score that’s going to change the Western world or the musical as we presently know it. But I just hope it’s fun.”

Drinking coffee in an upstairs lounge at the Winter Garden on a Friday evening, Mr. Lloyd Webber had flown in from London a few hours earlier. While there, he had cast a rare vote in the House of Lords that would have helped advance a plan to cut tax credits for workers in low-paying jobs and for people with children. (The plan was blocked anyway; Mr. Lloyd Webber has said he was voting to prevent the House of Lords from overruling the House of Commons.)

Here he was clothed casually, as he often is, wearing a dress shirt with a couple of open buttons, jeans and sneakers, and he spoke in a polite but halting manner, occasionally referring to himself in the third person. (“One would be lying if one didn’t say that one had melodies that I keep in my back pocket.”)

He does not neatly fit the definition of a British noble or a popular composer, and no one is more aware of this than he is. Going back to his youth, Mr. Lloyd Webber said, “I was an odd animal, really.”

He grew up loving the musicals of Rodgers and Hammerstein and knowing “South Pacific” practically by heart. His father, William, was the director of the London College of Music, but he also sneaked young Andrew into a movie theater to see Elvis Presley’s “Jailhouse Rock” and taught him a valuable lesson about personal taste.