Nathan Fillion, Stana Katic React to That Crazy ‘Castle’ Series Finale: Read Here

It ended with a sob. After eight seasons (and recently revealed behind-the-scenes drama), the series finale of ABC's Castle aired on Monday, May 16, and the drama's two leads, Nathan Fillion and Stana Katic, as well as its showrunners all took to Twitter to react to the emotional, anxiety-inducing episode.

Fillion, 45, who's played titular novelist Rick Castle since March 2009, live-tweeted the roller-coaster finale on Monday night, and thanked viewers for their support.

ABC

ABC announced last week that it was canceling Castle along with another popular drama, Nashville, causing a firestorm on social media from devoted fans. Fillion joked about the series' cancellation on Monday night, in response to some fans complaining that he was spoiling the episode with his live updates.

"But what are they going to do? Fire me?" Fillion replied. Despite the wisecrack, series creator Andrew Marlowe posted a kind message for the star. “Thank you to @NathanFillion for eight seasons of dedication, creativity, and leadership as #Castle. Can’t wait to see how you wow us next!" he tweeted.

Marlowe then directed his attention to other lead Katic, who played NYPD Captain Kate Beckett and wife of Richard Castle. "@Stana_Katic Thank you for all the gifts you bestowed on Katherine Beckett. The world is a richer place because of her… and you. #Castle And a very special thanks to all the #Castle fans & especially @CastleTV for all your support over our 8 seasons. You made the ride a joy."

Katic, 38, reacted by retweeting Marlowe's message with a kiss emoji.

Us Weekly exclusively revealed that Katic and her onscreen husband Fillion did not get along for years. “Stana Katic and Nathan Fillion completely despise each other,” an insider previously told Us. “They will not speak when they are off set, and this has been going on for seasons now."

She did not join Fillion and other cast members, including Toks Olagundoye and Molly Quinn, during their intimate viewing party on Monday night. "I love these people!!!!!! #CastleFinale," Olagundoye tweeted, while Quinn shared several updates from the show.

Marlowe wasn't the only crew member to get sentimental on Monday night. Showrunners Alexi Hawley and Terence Paul Winter also posted a sweet note, thanking their cast and viewers for eight seasons of fun.

"While we’re still trying to process all the emotions stirred up by recent events, the feeling that stands head and shoulders above all else, is gratitude," the executive producers wrote in their letter. "Eight seasons. A hundred and seventy three episodes. None of it would have been possible without you — our loyal and passionate fans. You are the reason this show survived and thrived. Without you carving out ‘Castle Mondays’ every week, we would never have been able to make the show we love for as long as we did. So thank you. And thanks to Andrew Marlowe for creating such a delightful world, centered around a love story for the ages. It was an honor and privilege to shepherd the story of Castle and Beckett this season. And finally, thank you to our cast and crew, who have been our family for these last eight years. Who elevated every script by investing the best of themselves into each episode. We will miss you profoundly. Alexi and Terence."

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