Fillion is a longtime collaborator with Gunn as they've worked together on Slither, PG-Porn, and Super. Gunn also went on to specify that the cameo is being done as a favor to him. SO with that said, there is no information on exactly who or what Fillion will be appearing as, but it is sure to be enjoyable. You might recognize him from television shows such as Castle, Firefly, and Buffy the Vampire Slayer. He's also done voice work for Robot Chicken, Halo 3, Halo: Reach, and King of the Hill. We will find out when Guardians of the Galaxy hits theaters on August 1st.
