Oscar-nominated actress and singer Ronee Sue Blakley has filed a defamation lawsuit against her screenwriter ex Carroll Cartwright amid allegations of defamation relating to his 2012 film What Maisie Knew.

Cartwright co-wrote the script for the drama, which was said to be an adaptation of Henry James' 1897 novel of the same name.

The story followed a young girl who was used as a pawn in a bitter custody battle between her abusive mother Susanna, played onscreen by Julianne Moore, and her father Beale, portrayed by Steve Coogan.

However, Blakley is convinced Cartwright used aspects of their own lengthy custody fight over their daughter Sarah in the film and now she is suing, citing "libel in fiction".

In her complaint, filed in Los Angeles Superior Court, her lawyer writes, "If Susanna had been an entirely fictional character, this lawsuit would never have been filed. But that is not the case. Cartwright, who co-wrote the screenplay of the Film, has admitted that it is closely based on his own first hand (sic) personal experience of a lengthy and acrimonious battle for the custody of his daughter, Sarah."

The papers continue: "Cartwright wrote the screenplay to further his own feelings of hatred for Blakley by maliciously and falsely portraying her as a selfish and uncaring mother, when in fact she was a devoted and loving parent. This false depiction of Blakley has damaged her reputation and caused her to suffer severe emotional distress."

Blakley, known for her roles in 1975 movie Nashville and A Nightmare on Elm Street in 1984, is suing for $3 million (£1.9 million) in damages.