Nathan Fillion is just as recognizable to crime drama fans as to sci-fi fans, precisely due to the roles of Richard Castle in "Castle" and John Nolan in "The Rookie."

Given their shared passion for crime-solving, fans may wonder which character would be the best at solving cases, and Fillion himself has an answer for this considerable debate.

He compared the two characters, stating Castle “has bizarre, terrible theories [...] but he eventually gets the guy always,” while Nolan “just has more crime versus murders.”

In the end, Fillion seemed to give Castle the upper hand, “I'm going to say by sheer number, John. But I'm going to say Rick Castle probably has solved far more murders, though."