The crime mystery series, which ran for eight seasons between 2009 and 2016, garnered the actor a huge following, and it's clear that the show still holds a special place in his heart. Taking to Instagram this week, Nathan shared a snap of himself in costume as his The Rookie character laying down a rose at a grave which bore the name 'Castle' on the tombstone - and fans found it absolutely hilarious!
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He captioned the funny snap: "Rest In Peace, buddy. There can be only one," and fans quickly flooded the comment section with their reactions.
"Hahaha, this is EPIC!" one wrote, while another fan added: "I miss that show so much!!!! Looooove Castle.. I enjoy The Rookie, but it's just not the same love."
Nathan shared the hilarious photo to his Instagram account
A third asked whether there was another tombstone for another one of Nathan's shows. They wrote: "Close to the Firefly tombstone?" referring to the short-lived sci-fi drama he starred in back in 2002.
The actor headlined the police drama for eight years before it was cancelled in 2016
Nathan first appeared on screens more than 25 years ago and has had an incredible career. As well as his roles in Castle and Firefly, he has also appeared in the likes of Desperate Housewives, Buffy the Vampire Slayer and Two Guys and a Girl.
Since 2018, Nathan has been keeping Sunday night TV viewers entertained thanks to his starring role on The Rookie, in which he plays a man who, after inadvertently helping police officers during a bank robbery, moves to Los Angeles to pursue a new career as a police officer.
The show is now in its fourth season and has featured several Castle cast reunions over the years. Many of his former co-stars, including Jon Huertas, Annie Wersching, Seamus Dever and Toks Olagundoye have made brief appearances on the drama over the last few years, much to the delight of fans.
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