‘Brooklyn Nine-Nine' Season 4 Cast: Nathan Fillion Of 'Castle' Guest Stars As Detective!

Nathan Fillion must be missing his character, Richard Castle, that he played on the now-canceled TV series "Castle." Hence, he has agreed to portray a similar character on "Brooklyn Nine-Nine" Season 4. According to the reports, his will be a guest appearance where he helps the leads solve a crime.

Since Fillion is being true to his character that he played in "Castle," there will be zero seriousness and all cockiness in his approach. In "Brooklyn Nine-Nine" Season 4, he will be introduced as Mark Devereaux, the star of a crime thriller television show called "Serve & Protect," Entertainment Weekly reported.

Apparently, he tags along with Jake (Andy Samberg) and Rosa (Stephanie Beatriz) because he thinks that playing a fake detective onscreen qualifies as enough experience to solve an actual crime in real life. "Brooklyn Nine-Nine" Season 4 could not get more "meta" than that!

Although not much is known about the crime itself, the only thing that is revealed is that the crime in question will also be seen taking place on the sets of his TV show, "Serve & Protect." In trying to be in so-called charming self on "Brooklyn Nine-Nine" Season 4, Fillion will end up annoying Jake, Movie Fone reported. Detective Peralta, on the other hand, will wave off the antics of Fillion's character as a joke but will be unpleasantly shocked when he finds out that Mark is not kidding about wanting to assist in solving the crime.

In "Castle" Fillion played the rich and handsome, but bored, crime novelist who pulls some strings to pair up as a consultant with Detective Kate Beckett (Stana Katic), despite her unwillingness, and helps the NYPD solve crimes. The highly successful series ran for eight seasons before getting canceled due to internal disputes last year. On "Brooklyn Nine-Nine" Season 4, Nathan Fillion will get the unique opportunity to relive a similar version of his old character once again.

There is still no word as to which episode Fillion's guest appearance might be in. "Brooklyn Nine-Nine" Season 4 returns from its winter hiatus sometime this spring.