Amidst all the rumors surrounding Nathan Fillion playing Nova in the Guardians of the Galaxy movie, director James Gunn not only debunked the Richard Rider rumor, but does confirm Fillion will cameo.
James Gunn took to his Twitter to confirm that Nathan Fillion has a small cameo role in Guardians of the Galaxy.
@JamesGunn) June 21, 2014
A while back saw Fillion confirm his cameo as well, where he mentioned to check the credits.
Possibly this could mean to check the credits for his name -- meaning we wouldn't see his face.
If true, maybe Nathan Fillion is appearing in disguise as an alien or voice-acting a character.
One guess is Nathan Fillion could be the voice of Cosmo; Marvel Studios president and producer Kevin Feige stated that fans of Cosmo will want to see the movie.