At only 26, Anna Kendrick has already been nominated for both a Tony and an Oscar. So it’s no wonder that after “Up in the Air,” the actress has been inundated with scripts. But the one she chose to accept—in addition to completing her role as Jessica Stanley in the “Twilight” series—was “50/50,” in which she plays a nervous young therapist counseling Adam (Joseph Gordon-Levitt), a twenty-seven year old diagnosed with a potentially fatal spine tumor. Like the downsizing specialist in “Air,” the character is a professional beginning her career, but as Kendrick explained during a recent Dallas interview, she’s rather different.

“I guess I would say that they’re similar only in that they’re both young professionals,” Kendrick said. “Natalie, in ‘Up in the Air,’ is efficient and proud and ambitious and she thinks she’s a genius. Katharine, I think, knows that it’s going badly and suspects that everybody else knows. Her drive doesn’t come from ambition, her drive comes from a genuine desire to help people, and she’s so excited about helping people that she’s not doing it.

“What attracted me to her was the idea that she’s the opposite side of the coin. She’s starting out at something, but she’s terrified that she doesn’t know what she’s doing. That vulnerability is so on the surface.”

Kendrick could understand the character because she had experienced a similar reaction to her success as an actress—“that suspicion that everybody knows you don’t belong. I think I was putting a lot of what I was going through into this movie because I felt like I didn’t belong on these red carpet, I didn’t have any business at these parties, pretending to be a movie star. So when I read this, I certainly could relate. I was really excited to have this as my personal therapy.”

Kendrick added, though, that while the therapist she plays isn’t terribly effective at her job, she doesn’t intend that to reflect on the entire profession. “I’ve always had a positive view of talk therapy,” she said, “never a negative view of that. I don’t want to do a disservice to an entire profession, but at the same time, this character is new and inexperienced, and young, and she’s not very good at her job. So I hope that people realize that’s not indicative of an entire group of people.

“The woman [counselor] that I met with, who was helping me, basically just talked to me about the mistakes she made when she was starting. And I tried to put all of that into Katherine—she’s making all those kinds of mistakes.

“I’d imagined that her [first] two patients were older and just wanted someone to talk to. This is the first person to come in and really challenge her, to say ‘That’s really a cliché,’ or ‘That’s not helping me.’ To really call her out. She really finds that to be a challenge, and when she’s challenged is really when she’s at her worst, when she retreats into her textbook and says all the wrong things when trying too hard to say the right ones.”

In time, however, Katherine and Adam find they have a good deal in common. “I think they connect when…she sort of forgets that it’s a patient-therapist relationship,” Kendrick said, “which to me says that she has good instincts and will be a good therapist. I think that moment is really important when she says, ‘I’m just trying the best I can.’ I think we all feel that way but are just too embarrassed to admit it.”

The chemistry between Kendrick and Gordon-Levitt onscreen is particularly noteworthy because they met only twenty minutes before filming one of their most important scenes together—the one she pointed to as the turning-point in their relationship. And it worked out remarkably well. “I didn’t know if Joe really found me that charming or he was such a good actor,” she said, adding with a self-deprecatory laugh that she thought it was “the latter—he’s just so good.”

How did Kendrick choose to do “50/50” of all the scripts she was offered after “Up in the Air”? “To me the most exciting thing in the world is when somebody says something that’s more honest than I would have been brave enough to say,” she replied. “You don’t always find that. But I think the honesty in this script is what attracted me to it. I wish there were a science to picking movies, and to acting. But if there was, anybody could do it. We’re all just trying to figure it out.

“A comedy about cancer—if this had gone badly, it would have been spectacularly bad. I just didn’t know how funny it was going to be and how much heart it was going to have. On the page I thought it was fantastic, but you can never really get a sense of the big cathartic moments and if they’re going to work. [Now] I’m really proud of this movie and I feel really lucky that it all worked out because can go in with the best intentions—we all do, no one sets out to make a bad movie—but sometimes it just gets away from you. You just try the best you can and leave a lot of it to luck.”