Over the weekend, audiences laughed (and cried) along with Joseph Gordon-Levitt and Seth Rogen in the heartfelt comedy "50/50," loosely based on writer Will Reiser's real-life battle with cancer. (Spoilers ahead!)

Gordon-Levitt's thoughtful portrayal of 27-year-old cancer patient Adam takes him on a journey from diagnosis to recovery, breaking up with girlfriend Rachael (Bryce Dallas Howard) and sparking a new relationship with therapist-in-training Katherine (Anna Kendrick) along the way. The budding romance is only teased, however, as the two never seal the deal with a kiss. It was a purposeful omission, the film's writer and stars said at the "50/50" premiere last week in New York.

"We very much resisted them kissing," Reiser told MTV News. "The movie is not a love story. It's about a guy's battle with cancer. If it turned into a love story at the end, we would be betraying what the movie is about. That kiss is the start of another movie."

Kendrick, in fact, was relieved she didn't have to smooch Gordon-Levitt, as they'd become good friends after weeks of filming together.

"The studio wanted to see us kiss at the end, actually. We were thinking about just trying it as an option," she explained. "Joe very wisely stood up and said, 'If we give it to them as an option, they will use it.' So we just decided not to do it, because it really just didn't feel right. And I was relieved, because I had known Joe for too long at that point. It's too weird once you think of someone as a friend to be like, 'OK, I guess we make out now?' "

But Kendrick probably shouldn't share that sentiment with Gordon-Levitt, because as he told it, he was pretty bummed he didn't get to kiss his leading lady. "It's a travesty," he said with a big grin. "It's a horrible injustice, and I'm writing a letter."

Check out everything we've got on "50/50."

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