Galaxy Quest is a 1999 American science fiction action comedy film directed by Dean Parisot and written by David Howard and Robert Gordon. A parody of science-fiction movies and series, notably Star Trek and its fandom, the film stars Tim Allen, Sigourney Weaver, Alan Rickman, Tony Shalhoub, Sam Rockwell, and Daryl Mitchell. The film depicts the cast of a defunct cult television series called Galaxy Quest, who are suddenly visited by actual aliens who believe the series to be an accurate documentary and become involved in a genuine intergalactic conflict. (Wikipedia)
http://cinematicdiversions.com/galaxy-quest-1999-review/