Nathan Fillion Reacts to Stana Katic’s Abrupt ‘Castle’ Exit Amid Tension Rumors

He speaks! Nathan Fillion has broken his silence following the news that his Castle costar Stana Katic is leaving the ABC series after eight seasons.

"Castle has been one of the greatest joys of my creative life, and I hope the show continues on for years to come," Fillion, 45, said via Twitter on Tuesday, April 19. "Stana has been my partner all this time, and I thank her for creating the character of Beckett who will live on for all of us as one of the greatest police officers on television."

"I wish her well, and have no doubt she will succeed in everything she pursues," the Firefly alum continued. "She will be missed."

The network confirmed on Monday that Katic, 37, has decided to leave the show over budgetary reasons. However, a source told Us Weekly that there has been fierce tension on set between the two leads.

'Castle' stars Nathan Fillion as Richard Castle and Stana Katic as NYPD Detective Kate Beckett. Bob D'Amico/ABC via Getty Images

"Stana Katic and Nathan Fillion completely despise each other. They will not speak when they are off set, and this has been going on for seasons now," the insider told Us. "This season, it got so out of hand they made Stana and Nathan go to couples counseling together."

Fillion's team didn't respond to a request for comment, and Katic's rep told Us that the star "had absolutely no issues" with Fillion.

Katic and Fillion have starred on the series together since 2009, and there's a possibility that Fillion may still stay on for season 9, although the popular crime procedural has not yet been renewed. Katic, meanwhile, has so far kept mum about her departure from the series.

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