Martin Sheen confirms he will be back for The Amazing Spider-Man 2

Speaking to RTÉ's The Late Late Show, the actor still best known by many as Jed Bartlet revealed that despite his character's unfortunate stumble off his mortal coil in the previous Spidey adventure, he's been called back for more wise words-dispensing by director Marc Webb:

Sheen: "Well, they called me back. I don't know what the part's going to be but I'm going to be Uncle Ben once again in Spider-Man next year. We shoot in February."

Source - probably as some cheesy poignant flashback/dream