When “Stars Wars” fandom was reaching fever pitch late last year — ahead of the premiere of “The Force Awakens” — Luke Skywalker actor Mark Hamill noticed an uptick in the number of fans asking for his help verifying his own signature on movie posters and other memorabilia.
There was only one problem: He hadn't yet signed any posters for the new movie.
“As a joke at the London premiere, I said I'd only initial posters to reflect my contributions to the movie. And even then, I only did like three of those,” Hamill told the Los Angeles Times in an interview.
So he began to tweet back to his fans with a steady stream of...