After 3 seasons of building sexual tension, NCIS agents Deeks (Eric Christian Olsen) and Kensi (Daniela Ruah) had their first real on-screen kiss.

NCIS: Los Angeles left fans waiting on tenterhooks for the season premiere. With three quarters of the team in mortal danger, viewers are wondering what will become of the coworkers' budding romance.

"It wasn't a candlelit dinner," executive producer Shane Brennan told TV Guide. "It was almost a challenge that he threw down to her. I think it surprised both of them."

As partners, Deeks and Kensi always possessed a certain playful chemistry. Deeks unexpectedly swept in for the climactic kiss when the pressure of the mission and the partners ambiguous relationship began to take its toll on both agents.

When season 5 picks up, however, what will become of the pair? Kensi never really replied to Deeks after he kissed her and who knows what Deek's state of mind will be post-torture.

While it is clear Kensi was ruffled by Deeks' supposed relationship in "Parley," how would Deeks react if Kensi's ex-fiancé Jack were to show up on the scene. According to Brennan, it is a definite possibility.

"Yes," Brennan said when TV Line asked if Jack could show up in a future episode. ""I answered you pretty quickly, so perhaps it's something we are already thinking about."

It appears the agents' already complicated relationship may get a little more tangled in season 5.

Tags: NCIS: LA