Shortly after the production team changed the title of "NCIS: LA" season 7 episode 2 from "Aegis" to "Citadel," production manager Rick Tunell dropped a teaser via Twitter, saying that the episode will introduce a character that is new to the series but is also someone fans "want to see." 

"Tech scouting ep#702. You'll meet someone you've been wanting to meet. #ncisla," Tunell posted. 

According to a report from Enstarz, the most likely candidate for this new character is Callen's (Chris O'Donnell) long-lost father. The character was long believed to be dead and the show has been quite slow in giving the audience any revelation regarding his fate, but the season 6 finale revealed that he is indeed well and alive. 

Callen's father perfectly fits the bill. The character hasn't been revealed on the show yet, making him a new character if he does get some screen time in season 7, but he has been mentioned and discussed on the show for so long that fans do want to see him and see an end to Callen's search.  

Callen's hunt for his father has been spread across the seasons with tidbits of information coming sparsely between episodes. Season 7 might be able to pick up this storyline if it focuses on Callen dropping everything else to save his father now that he knows that the latter is alive.  

The report also surmises that the mystery character might be Deeks' (Eric Christian Olsen) mother. Deeks previously stated on the show that he has no next of kin, but in season 5, this was debunked when a plotline was introduced that was meant to bring his mother on the show. This has led to other revelations, but his mom has yet to be revealed.

"NCIS: Los Angeles" is currently in production and is scheduled to premiere this Sept. 21.