Professor Layton and the Eternal Diva (レイトン教授と永遠の歌姫, Reiton-kyōju to Eien no Utahime) is a 2009 Japanese animated mystery film directed by Masakazu Hashimoto, written by Aya Matsui from a story by Akihiro Hino and produced by P.A. Works and OLM. The film is based on the Professor Layton video game series by Level-5, taking place between the events of the video games Professor Layton and the Last Specter and Professor Layton and the Miracle Mask. In the story, renowned opera star Janice Quatlane contacts her former teacher, Professor Hershel Layton, after encountering a young girl who claims to be the reincarnation of her dead friend. While Layton and his apprentice, Luke Triton, are attending one of Janice's performances, they get unwillingly pulled into a puzzle-themed battle royal where the winner will apparently receive "the gift of eternal life". According to Level-5, the film stays true to the games, with music, puzzles and characters.

An English-language version was released by Manga Entertainment in the United Kingdom on October 18, 2010, around the same time as Professor Layton and the Unwound Future was released, with a British voice cast (including Maria Darling reprising her role of Luke from the UK releases of the games). The film was released in the United States on November 8, 2011 by Viz Media and received generally positive reviews from critics.