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Aquaman type Movie genre Action Adventure Where to watch Close Streaming Options

A member of Hollywood royalty has a secret role in Warner Bros.’ upcoming Aquaman.

None other than Oscar-winner Julie Andrews has a previously unannounced part to play in the superhero adventure, EW has learned exclusively.

The Sound of Music actress voices the mythic Karathen, an undersea creature that holds the key to Arthur Curry’s (Jason Momoa) quest to unite the Atlantean and surface worlds.

The casting is particularly interesting as Aquaman is going head-to-head at the box office next month against Disney’s Mary Poppins Returns — the sequel to Andrews’ 1964 classic — which also has a live-action plus animation underwater sequence. Andrews declined to appear in the sequel, as she reportedly didn’t want to distract from star Emily Blunt’s take on the iconic role, though is said to be fully supportive of the project.

“We wanted the Karathen to have the voice of a classic British actress, albeit somewhat digitally altered,” explained Aquaman producer Peter Safran. “And when we found out Julie was interested and available and excited to do it, casting her was a no-brainer.”

As for the timing of going against Mary Poppins Returns, Safran jokingly added, “Who knew that Aquaman would have the real Mary Poppins this Christmas?”

Image zoom Warner Bros. Pictures; James D. Morgan/Getty Images

Andrews hasn’t appeared in a film in nearly a decade, but has lent her unmistakable voice to other big screen projects over the last decade (such as Despicable Me 3 and Shrek Forever After) and appeared in the Netflix series Julie’s Greenroom.

Aquaman is released in theaters Dec. 21, during a highly competitive period at the box office. In addition to Poppins, there’s also the Transformers spinoff Bumblebee and the Will Ferrell and John C. Reilly comedy Holmes & Watson. Previously, the James Cameron-Robert Rodriguez manga adaptation Alita: Battle Angel was also supposed to open that weekend, but has been pushed to Feb. 14.

In an unusual move, Aquaman will also have advance screenings for Amazon Prime members on Dec. 15.

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