The 28-year-old plays the role of a folk singer Greta in the movie and believes she has had her share of singing through this movie.
"I literally was given the songs for this about a week before we started shooting. We had to go straight into the studio, and I had never sung before and I had to just kind of try and figure it out. So that's what I did," eonline.com quoted Knightley as saying.
"I'm not going to do it again, that was it. No, no, no, that was my one and only. Come and see this film, that'll be it," she added.