Harry Potter and the Deathly Hallows: Part Two was awarded the prize on the red carpet, as dozens of celebrities arrived for this year's annual SAG ceremony.
The win comes as the eight-part blockbuster lines up for its last chance to clinch Oscar glory next month; something which has so far eluded film franchise.
The winners at the SAG ceremony typically go on to earn Oscars. The film has been nominated for two Oscars at this year's Academy Awards on February 26.