A little-known Ukrainian singer is threatening to sue Carly Rae Jepsen for allegedly stealing her Christmas tune and turning it into mega-hit Call Me Maybe.

Aza has asked her lawyer Barry Rothman to file suit in Los Angeles on Thursday (08Nov12), insisting the Canadian pop star's song is a copy of her festive tune Hunky Santa.

According to the documents, obtained by Tmz.com, the Ukrainian is suing for unspecified damages. She is also suing Jepsen's manager, Scooter Braun.

Aza tells Tmz, "I'm shocked and surprised that these people wanted to sample my lyrics on their song. They didn't ask me for permission, they just took it. That's why I filed this lawsuit. When I first heard it on the radio, I was driving and almost got into an accident. I couldn't believe what I was hearing."

However, Jepsen's representative has dismissed the allegations, stating: "This is completely false and lawyers will deal with this. Everyone knows she (Jepsen) is a songwriter. She is not spending a lot of time listening to Ukrainian radio."