Anastasia, the new Broadway stage musical adaptation of the 1997 animated film, is being sued by an heir of playwright Marcelle Maurette, who also wrote a play based on the life of the Grand Duchess Anastasia Nikolaevna of Russia. Maurette’s Anastasia opened on Broadway in 1954.

According to the New York Post, the lawsuit claims that the musical’s plot borrows heavily from Maurette’s play. The 1997 animated film has been expanded and humanized by Tony Award-winning playwright Terrence McNally to incorporate historic and political context of the era. It had its world premiere last spring at Hartford Stage.

Maurette’s heirs are seeking an injunction to bar the show from opening until a licensing agreement can be reached. Stage Entertainment, which produces along with Tom Kirdahy and Bill Taylor, stated that there was no merit to the lawsuit and that the musical is based on the story of Anastasia Romanov’s life.

The show’s producers issued a statement in response to the lawsuit: “The Plaintiff’s case is wholly without merit. While the works may start with the basic idea of the historical story of the real-life Anastasia Romanov, copyright law does not protect ideas or historical facts. Moreover, the works involved are not similar: the Broadway production has a different plot, different characters, and different settings, not to mention the numerous songs that appear in the Broadway musical that do not appear in Plaintiff’s straight play. We are particularly disappointed about the filing as the production went out of its way to explain these myriad differences to Mr. Becdelievre to resolve the issue. We look forward to responding to the claims in court.”

The musical, which features a score by Tony winners Lynn Ahrens and Stephen Flaherty, is one of the most anticipated productions of the Broadway season.