Television’s Firefly and Castle actor Nathan Fillion has joined the cast of Guardians of the Galaxy Vol. 2 as a major character from the comic books. Spoiler alert: he will be portraying Simon Williams, a.k.a. Wonder Man!

Wonder Man’s backstory in the Marvel series begins with him as a former villain – member of the Masters of Evil and brother to the Grim Reaper. He reforms and becomes joins up with the Avengers. He soon retires to pursue somewhat of a normal life in the form of an acting career, but later gets dragged back into the superhero fold – despite becoming a pacifist – as a member of the Avengers Unity Division.

Fan photos recently surfaced online of Simon Williams easter eggs. They don’t reveal Fillion suiting up for the Wonder Man role just yet, but in mock movie posters for a fictional “Simon Williams Film Festival” in Cartersville, GA. The posters feature Williams in several genre-specific films: there is one romantic comedy titled Oh, Rebecca, a Steve Jobs copycat film in which he portrays Tony Stark, a supernatural sequel movie, and an old school barbarian film, Arkon. The extent to which we will get to see Fillion in the new role beyond this film festival set is still unclear, however.

As Fillion is introduced into the Guardians universe, he will be joining director James Gunn along with returning stars Chris Pratt, Zoe Saldana, Vin Diesel, Karen Gillian, Bradley Cooper, and Dave Bautista. The plot will follow the team solves the mystery of Peter Quill’s (Pratt) parentage. The film is currently being shot at various locations in Georgia and is slated for release on May 5, 2017.

See the photo below depicting Fillion as Simon Williams in some of his various film roles, and head to comicbook.com for some (grainy) close-ups.