“CASTLE” hunk NATHAN FILLION is tying the knot – thanks to two of his co-stars who convinced the once-confirmed bachelor it was finally time to settle down. 
The handsome 43-year-old actor will soon be heading to Barcelona, Spain, to ask the parents of his gorgeous girlfriend Christina Ochoa, 29, for her hand in marriage, say insiders. 
“Up until now, Nathan has been telling friends he was in no hurry to marry,” revealed a close source. 
But when Nathan saw the happiness of his newlywed co-star Jon Huertas, who plays homicide detective Javier Esposito on the hit ABC crime series, he decided to step up his own marriage plans before he lost the girl of his dreams. 
“Jon just got back from his Mexican honeymoon and is so happy these days that it made Nathan want to feel the same way,” said the source. 
And James Brolin, who guest stars as Nathan’s TV father, told the actor that at age 43, it was time to make his move, revealed the source. 
On the show, Nathan plays famous mystery writer Richard Castle, who moonlights helping the NYPD homi¬cide division solve difficult cases. In real life, he solved the mystery of how to land Christina, a gifted actress and model, who’s also an accomplished writer and marine biologist.
The two began dating late last summer, but their busy schedules often kept them apart. 
Wedding bells should ring soon, said the source, adding: “All Nathan has to do is win the hearts of Christina’s family with his charm.”