The actress was determined to do everything she could to appear in the movie - in which she played a beauty queen-turned-singer - alongside Gwyneth Paltrow because she fell in love with the project and was pleased when `Gossip Girl` producers were able to free up her time to make the film.
She said: "Obviously we`re under contract for a certain amount of time in `Gossip Girl`. In the fourth year they started going, `OK, we know the timing of things. We know how much we need you and how much we don`t,` so they`ve been kind enough to let us out.
"When `Country Strong` came up though, I threatened everybody including my manager, my agent and everybody I worked with. I was like, `If I can`t do this, if we can`t work out the schedule, I`m moving to Costa Rica, I`m turning off my phone and I-m never going to work again.`
"I was bluffing of course but it worked."
Leighton is more proud of `Country Strong` than any of her other work and thinks it has appeal for everyone.
She told Company magazine: "It`s a beautiful movie. The best thing I`ve ever done.
"There`s something for everyone - the music, the performances, which are super-fun and energetic. Then there are the love stories. There are the struggles of friendships and all the drama that comes with the limelight."