The film, which is currently shooting, is a sequel to the 2004 film "National Treasure," starring Nicolas Cage, who is reprising his role as a treasure hunter.
Mirren will play Emily Appleton, the mother of Cage's character. Ed Harris (Wrecks at the Public Theater), another new addition to the cast, will play the villain.
In the sequel, which will be released Dec. 21, Cage's character tries to find the truth behind Abraham Lincoln's murder by looking for missing pages from John Wilkes Booth's diary.
Jon Turteltaub is reprising his role as director. Returning cast members also include Diane Kruger, Justin Bartha, Jon Voight and Harvey Keitel. Jerry Bruckheimer Films is producing with Sparkler Entertainment.
This year Mirren won the Academy Award, Golden Globe, SAG, BAFTA and Critic's Choice awards for "The Queen"; won Emmy, Golden Globe and SAG Awards For HBO's "Elizabeth I"; and received a Golden Globe nomination for PBS' "Prime Suspect: The Final Act," which had previously won her an Emmy and three BAFTA Awards. Her many stage credits include Broadway productions of Dance of Death and A Month in the Country.