The cases are heating up on NCIS: Los Angeles, but so is Callen's love life.

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The notoriously single agent will get a love interest late in season 6, and his new beau will have a link to his tangled past.

"What I do know about it is the woman is related to someone that has a connection to Callen's past, someone that we've seen before in episodes," said actor Chris O'Donnell (Callen), according to TV Guide. "It'll be fun to explore that part of Callen. He's such a private guy and kind of a simple guy. ... That personal relationship side of him we haven't really explored that much."

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Callen had a bit of a relationship last season, but his seldom seen girlfriend has yet to make an appearance in season 6. It looks like that flame will quickly burn itself out however, and make way this new relationship - hopefully one will see more of than Callen's previous love interests.

Who do you think this new woman is related to? Tell us your theories in the comments below!

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

Tags: NCIS: LA NCIS: Los Angeles television CBS