Nathan Fillion has revealed that he wants Castle to run for six or seven years.
The 41-year-old star told Digital Spy that he wants his ABC crime drama to "end strong" and not "die a slow death".
"I think something that you guys here [in the UK] do really well is take shows, have incredible stories and then finish strong and wrap them up," said the actor. "That's something I can really appreciate.
"What I don't want to see happen to Castle is... I don't want to see it peter out and die a slow death, and be forced out."