Nathan Fillion will be guest starring on Brooklyn Nine-Nine! 
Nathan Fillion is getting meta with his next TV gig.
The Castle vet will guest-star on Fox’s Brooklyn Nine-Nine as Mark Devereaux, the star of a Law & Order-type series titled Serve & Protect, EW.com reports.
Mark thinks playing a detective on TV makes him qualified to help Jake (Andy Samberg) and Rosa (Stephanie Beatriz) investigate a crime that occurred on the set of his crime drama.
Source: TV Line
