“Castle” lead star Nathan Fillion has spoken about the shocking exit of co-star Stana Katic in the series, saying the actress will be missed in the show.

ABC earlier confirmed that Katic and Tamala Jones are set to leave “Castle” before season nine.

Fillion broke his silence about the news and posted a message on his Twitter account.

“Castle has been one of the greatest joys of my creative life, and I hope the show continues on for years to come. 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. She will be missed,” the actor wrote.

Fillion played the mystery novel writer Richard Castle on the ABC hit series. Katic, on the other hand, portrayed NYPD Detective Kate Beckett, who is also Castle’s wife.

“Castle” creator Andrew W. Marlowe also address Katic’s exit on Twitter. “Heartbroken. There are no words. #nmc,” he wrote.

It is unclear what “nmc” stands for, but People magazine guessed it could be “no more Castle,” “no more comment,” or “not my choice.”

Meanwhile, the network also remains mum on the reason why they had to let go of their leading actress. However, according to The Hollywood Reporter, it was a financial decision.

Sources tell THR that ABC has thought of writing out Katic’s character at the end of season seven but pulled back when the network was slammed after Patrick Dempsey’s character, Derek Shepard, in “Grey’s Anatomy” was killed off.

THR noted that if “Castle” will be renewed for season nine without Katic, the series could focus more on a case-of-the-week format rather than the romance between Castle and Beckett.

“Castle” it was not among the 15 shows that ABC recently renewed. Deadline reported that the network is eyeing a shortened season 9 with just 13 episodes.

However, THR noted that ABC has already said that since the show has not yet been renewed, a decision on episode count has not been made.