When people noticed that Danny Elfman got an additional music credit on the poster for Avengers: Age of Ultron, speculation ran rampant. Would he be bringing his theme from Sam Raimi's Spider-Man to Age of Ultron? Was this the clue that revealed Spidey was going to make his MCU debut in just a few months?
Nothing short of seeing the actual film will end that theory, but if you want to believe Elfman himself, he spilled the beans on the radio today. Talking about rejiggering other composer's scores, Elfman said:
I was doing the same thing actually just last week because I’ve contributed music to the new Avengers movie. I took part of Alan Silvestri’s theme on the original [movie], which I really liked, and I pulled it into it new theme, which became kind of a hybrid. I really enjoyed that.
Brian Tyler is scoring the film itself, so I'm not quite sure why he couldn't have just pulled in Silvestri's theme (which is pretty good, actually - after complaining about the lack of hero themes last week I gave that another listen and find myself quite enjoying it). But for whatever reason Marvel hired Elfman to get the job done. Maybe they decided late in the process that they wanted the theme to return; consistent themes haven't been the studio's strongest suit.
Of course Elfman could always be lying, but why would he be? He wasn't asked what he did on Age of Ultron, he volunteered it. Unless it was psyops, intended to make us think he was volunteering the information because it's true when in fact it is the Spidey theme!
It's not the Spidey theme. Here's Silvestri's Avengers theme: