Nathan Fillion will appear in Marvels Guardians of the Galaxy, director James Gunn revealed this weekend on Twitter. The role is extremely brief, says Gunn, who said on Twitter that the Firefly and Castle star has a a very small fun cameo he did as a favor to me. Fillion had previously teased that hed make it into the films credits, and rumors intensified this week after a report from Latino Review claimed Fillion would have a more substantial role in the film as Nova. @STARS_TyranT: Are the rumours true that he has some part in the film? @nathanfillion has a very small fun cameo he did as a favor to me. — James Gunn (@JamesGunn) June 21, 2014