ABC’s Castle has been on the air for eight seasons now, so it’s surprising that we’re only now hearing this particular bit of casting news. Castle star Nathan Fillion used to be on a show called Firefly, the very short-lived but much loved sci-fi series of cowboy Han Solos that you may have heard of. The show's strong cult following will appreciate that the showrunners at Castle are cashing it in again with an appearance from Fillion’s former cast member, Jewel Staite.According to TVLine , Jewel Staite will appear in a guest star role, which should be a blow to anyone hoping she'd stick around for non-spacefaring mysteries, and herdebut will come in the ongoing eighth season. This news was confirmed by showrunners Terence Paul Winter and Alexi Hawley.The actress' character will be a director of a "Shakespearean Broadway staging whose movie star lead turns up dead." This will, of course, attract the attention of Castle and company, where – and this is just me guessing/crossing my fingers – Castle will have to step into the lead role of play. This episode, which will be the 20th in the season, will be titled “Much Ado About Murder” and will air on May 2.This will hardly be the first Firefly guest star on Castle. Previous cast members such as Adam Baldwin, Gina Torres, and most recently Summer Glau (who guest-starred as a rival private detective) have appeared at one point or another on’s long run. Outside of TV, the group has also gotten together for conventions and special reunions.On Firefly, Jewel Staite played Kaylee Frye, the ship’s plucky young mechanic who provided some of the shows comic relief and heart. She also provided some laughs on former co-star Alan Tudyk's web series, where she appeared as a cosplayer posing as Nathan Fillion's Captain Mal Reynolds. But she's just as good at drama, as evidenced by major roles on shows such as the sci-fi show Stargate Atlantis and the drama series. Her sci-fi cred is also intact thanks to a guest role on The CW's Legends of Tomorrow Even though Firefly was canceled shortly into its first season due to poor ratings, the show has continued to live on in multiple forms such as in a comic book and a role playing game. And it allows for the different actors' fans to get cheerworthy moments like these when they collide on new projects.airs Monday nights on ABC.