Confirming that Marvel will do anything to pander to nerds--with the exception of letting Edgar Wright make a movie--director James Gunn has finally validated the old rumor that Nathan Fillion would show up in Guardians of the Galaxy. Fillion had previously alluded to appearing in the film, and now Gunn has tweeted that the actor indeed "has a very small fun cameo he did as a favor to me." As a favor to ABC, Fillion also still stars in Castle. It airs weekly! Still!