Mexican pop star Gloria Trevi is threatening legal action against the producers of a new biopic, insisting she didn't authorise the script.

Lawyers representing the singer have sent a cease-and-desist letter to movie executives, ordering them to shut down the production, which began on 29 November (13), according to The Hollywood Reporter.

Oscar-winning Lord of the Rings producer Barrie Osborne is one of the movie bosses behind the project, titled Gloria, which stars Sofia Espinosa as the star.

Trevi's lawyer says, "The project is being developed without script authorisation on behalf of Gloria Trevi. In addition, the limited authorisation that might have existed under contract has expired and it was not and will not be renewed by Gloria."