Since its debut at the Sundance Film Festival early this year, there’s been plenty of awards buzz for “The Sessions,” with stars John Hawkes and Helen Hunt considered a sure bet for Oscar attention.

Standing just outside that spotlight is an up-and-coming actress for whom this movie might be the big break all performers crave. “I had no sense in signing on to do (‘The Sessions’) that it would turn into what it’s become,” said Annika Marks, on the phone from her Los Angeles home last month.

In the film, she plays Amanda, a hired caregiver for Berkeley writer Mark O’Brien (Hawkes, playing a real-life character), who after childhood polio must spend most of his hours confined to an iron lung. At 38, he longs to lose his virginity, and after his crush on Amanda goes nowhere, he turns to a sex surrogate (Hunt). It’s a gentle, funny, unexpectedly touching film — O’Brien never succumbs to self-pity, and Hunt’s character finds herself deeply moved by him — and a genuine crowd pleaser.

Marks, born in Sweden while her father was attending graduate school there, “moved around a bit” with her family as a child before settling in Bellevue, Wash. (where her parents still live) when she was 13. She attended Bellevue High and studied dance at Cornish College of the Arts and acting at Seattle Children’s Theater — “a fantastic place to be young and in the performing arts.” Teachers Rita Giomi and Amy Harris, in particular, helped her prepare for an audition for New York’s Circle in the Square Theatre School, where she was accepted after high school.

After time in New York trying to jump-start a theater career, Marks moved to Los Angeles (“there’s more theater here than anyone thinks there is”) six years ago, and has divided her time between the stage and screen. Her credits include roles in the movie “Mona Lisa Smile,” the TV series “Southland” and numerous stage productions.

The audition for “The Sessions,” in front of writer/director Ben Lewin (himself a polio survivor), was one of many for this working actor, but she landed the part and quickly dove into research. She studied writings by O’Brien (who died in 1999), particularly the autobiographical essay on which the film is based, and watched a short documentary about O’Brien, “Breathing Lessons.”

But nothing quite prepared her for the impact of working with Hawkes. The actor, an Oscar nominee for “Winter’s Bone,” faced enormous physical challenges: acting with almost no movement, lying on a ball to contort his body as O’Brien’s was, learning to use a mouth-stick to type and dial a phone, losing himself within a character.

“It was so extraordinary to be witnessing that type of work. It doesn’t seem like it’s humanly possible, what he’s doing,” Marks said. “I came home from the first day of shooting and said to my fiance, ‘I swear to God, he’s going to win an Oscar.’ ”

Marks shared in the film’s Special Jury Award for Ensemble Acting at Sundance, and has since traveled with the film to other festivals. She’s happily noticing that, thanks to “The Sessions,” more opportunities are coming her way. “The tides are definitely shifting, which is incredibly cool and I’m really, really grateful for it.”

Marks recently tested for her first TV pilot, and has several film and stage projects in the works, but “The Sessions” will remain a treasured experience.

“I struggle with feeling like I really deserve any kind of award for acting, as John and Helen stand alone, but I’m really honored to be included in any of it,” she said of the Sundance recognition. “I’m the luckiest actor in the world that I got to do this.”