The War and Peace actress has given her fans a taste of her acclaimed performance in Wild Rose with a cover of the Primal Scream hit "Country Girl."
The soundtrack, which will be released on 12 April to coincide with the launch of the film, also features a host of classic and modern country songs, including some co-written by Buckley.
The 29-year-old, who launched the film in Glasgow this week, told The Scotsman she was "******* myself" about the reaction of Glaswegians to the film.
She said she had “worked my **** off” to try to give a convincing performance as a cleaner struggling to pursue her dreams of stardom after getting out of jail.
The 29-year-old made several incognito visits to Glasgow’s famous Grand Ole Opry club - which features in several key scenes - and went drinking with the cast and crew to pubs like The Laurieston Bar and The Ben Nevis to try to get into “the Weegie mentality.”
Buckley, who stars opposite Julie Walters in the new film. said she even tied to dupe shopkeepers around the city by buying cigarettes in her adopted accent. She returned to the city for the Scottish premiere of Wild Rose at the Glasgow Film Festival and performed several songs from the soundtrack at an after-party at the Grand Ole Opry.
Buckley said: "Being a Glasgow girl is so much part of Rose-Lynn’s make-up.
“Honest to God, I love Glasgow so much now. It stole my heart. The people are so open and there is a real humanity behind Glaswegians.
“I was so nervous that I wouldn’t be authentic, but I worked my **** off so that I could get a close to the core as I possibly could.
“I based myself in Glasgow for a month before we started shooting. I was working with a dialect coach and the two of us would go out and I’d speak in a Glasgow accent all day.
“I basically just took to the streets and also went into different newsagents around Glasgow and tried to ask for a packet of fags.
“I took a lot of trips to The Ben Nevis, The Laurieston and all these other joints. They’re pure rust and real life.
“When you fall in love with the city and you fall in love with the people and fall in love with the character who symbolises all that in some way it is kind of scary letting it out.
“I want to do Glasgow proud. It means a lot to me.
“We did a cast and crew screening a few months ago (in Glasgow) and it was the most nervous I was. I don’t think I took a breath.
“When the film finished a woman turned around and gave me a hug. I literally just burst out crying.”
Wild Rose sees Buckley play a young country music fan struggling to balance her ambition of becoming a singing star with the reality of bringing up two young children - only to get an unlikely lucky break after taking a cleaning job brings her closer to realising her Nashville dreams.
The film, which has already been hailed as Scotland's answer to A Star Is Born and Billy Elliot by critics, was written by Glasgow-born screenwriter Nicole Taylor and inspired by her discovery of country as a teenager growing up in the city.
Taylor said: ""County has been an absolute obsession of mine since I was about 12 or 12.
"I should have been cutting about going to East 17 or Take That concerts, but I was just wowed by the songwriting. I would skip school to go up and see Garth Brooks in Aberdeen concert and started following Lyle Lovett down to Manchester.
"I loved country back when it was the love that dare not speak its name. It used to be really uncool before Taylor Swift came along and it suddenly became really popular, but I was hanging in there through all those geek years.
"I always just took it for granted that Glasgow had a big country scene. I got to see some amazing people when I was growing up at the Royal Concert Hall and the Old Fruitmarket. Then there was the Grand Ole Opry, which I used to go to on a Saturday night, which is such a friendly and wicked place."
Taylor said she was beginning to think Wild Rose would never get made when producer Faye Ward sent the script to Harper, a friend in the industry. Not only did he want to direct it, but he also knew who he wanted to star in it.
Taylor added: "He had Jessie in mind from the first page.
"I got sent a little video of her singing - it was an amazing moment. I was like: 'Yes. we've found Rose-Lynn.' I knew it right away. She even looked like her. When I met her a week later I knew she was the one. It was like we were on a date.
“It took a long time for me to write the script, partly because it was my first film, but also because it’s a very personal story to me.
“Now, in retrospect, I think we were waiting for the right person to play Rose-Lynn. Now I think it could only have been Jessie. Unless you have a voice of that power there would have been no point in making the film.”
Killarney-born Buckley’s performance has already drawn comparisons from Hollywood critics to Lady Gaga’s character in the new version of A Star Is Born after Wild Rose had its world premiere at the Toronto International Film Festival last year.
Buckley added: “The themes in the film are relevant all over the world. It’s about struggling to want something for yourself. I hope it leaves people feeling that they can break down those four walls and go after something that they want.
“Rose-Lynn is a bit like an electrical bolt. You need her to light up your life but you’re also afraid she might explode.
“You will her on to have the life that she wants, but are also worried for the life that she wants. She is courageous, strong-willed, tenacious and has real fight in her.”