Studio execs have swiftly moved to deny the accusation, made by the estate of the late playwright Paul Zindel.
It is alleged that his 1969 work Let Me Hear Your Whisper has several striking similarities with Guillermo del Toro’s acclaimed motion picture.
Both pieces are set in a research facility-type establishment, wherein a cleaner develops a bond with a captured creature.
In the case of Shape of Water, it’s Sally Hawkins’ deaf janitor falling for a captive marine monster, while in Let Me Hear You Whisper, the cleaner has a relationship of sorts with a dolphin.
In both pieces, the protagonists discover their creature is due to be killed, and plan to help it escape, according to Digital Spy.
The endings of both works are very different, however, and Fox Searchlight has strongly denied any allegations of plagiarism.
“Guillermo del Toro has never read nor seen Mr Zindel’s play in any form,” they said.
“Mr del Toro has had a 25-year career during which he has made 10 feature films and has always been very open about acknowledging his influences.
“If the Zindel family has questions about this original work, we welcome a conversation with them.”
Zindel’s son David had told the Guardian: “We are shocked that a major studio could make a film so obviously derived from my late father’s work without anyone recognising it and coming to us for the rights,”
The Shape of Water picked up the most Oscar nominations (13) and is the current bookies’ favourite to win Best Picture.