The cousin of “Top Gun: Maverick” screenwriter Eric Singer sued Paramount Pictures on Sunday, claiming he wrote key action scenes in the film without credit or compensation.

Shaun Gray, who has worked primarily as a visual effects artist, alleges that he worked on the script for five months with his cousin and with director Joseph Kosinski, and kept “meticulous, time-stamped files” documenting his contributions.

“This action seeks justice for Gray, a talented screenwriter, manipulated and exploited by Hollywood power players, and demands accountability from Defendants that profited prodigiously by misappropriating Gray’s creative work,” the lawsuit states.

Gray had worked with Singer before “Top Gun,” according to his IMDb profile. He is listed as an uncredited “writing consultant” on “Only the Brave,” a film about wildland firefighters written by Singer and directed by Kosinski. He is also identified as Singer’s writer’s assistant on “The International.”

His involvement in...