Callen's love life is heating up on NCIS: Los Angeles.

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Typically a loner, Callen's (Chris O'Donnell) life took an unexpected turn at the end of season 5. Thanks to Sam's (LL Cool J) unwavering commitment to keeping his partner from going through life alone, Callen has a steady girlfriend - one that even knows his true job as a gun-slinging agent.

In an interesting twist, Joelle (Elizabeth Bogush) will have a connection to a long-time, fan favorite member of the NCIS: LA team.

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"[She] ends up being connected to someone that we've seen in several past episodes," O'Donnell informed TV Guide. "There's more to the story."

Although Joelle's shocking past history could have to potentially to tear the two apart, Callen's own insecurities could easily torpedo to relationship as well.

"He doesn't let a lot of people into his life," O'Donnell said, according to TV Guide. "He's so insecure about that. He doesn't know anything about his real life."

Do you think Joelle and Callen stand a chance? Sound off in the comments below.

Find out more when NCIS: Los Angeles airs Mondays at 10 p.m. ET on CBS. Click the video below to see a preview for the series' next episode, "Black Wind."