The 75-year-old will star as Hespera, the daughter of Atlas, in the highly-anticipated DC Comics sequel Shazam! Fury Of The Gods.
Newcomer Rachel Zegler, who will appear in Steven Spielberg’s adaptation of West Side Story later this year, has also been added to the cast of Shazam!.
Zegler tweeted her excitement at the news of Dame Helens involvement, saying: “I’M GONNA BE IN A MOVIE WITH HELEN MIRREN?????”
Zachary Levi will return in the film’s lead role – a teenager who is turned into his adult superhero alter ego after yelling the word “shazam”, and being struck by the Living Lightning of the gods.
While he is bestowed with the powers of six gods – Soloman, Hercules, Atlas, Zeus, Achilles and Mercury – he is also trying to navigate high school.
The first film, which was released in 2019, rocketed straight to the top of the global box office rankings on its opening weekend, and has grossed around $366m (£266m) worldwide.
David F Sandberg, who celebrated Dame Helen’s involvement by tweeting “Awesome cast getting awesomer”, will return to direct the sequel.
A film based on Shazam! antagonist Black Adam is also in development, with Dwayne Johnson in the title role.