Sigourney Weaver is narrating the magical lives of whales.

In a PEOPLE exclusive look at the first trailer for Secrets of the Whales, it’s revealed that the Avatar actress will lend her voice to the upcoming National Geographic four-part special that premieres on Earth Day, April 22 on Disney+.

In the heartwarming trailer, the world’s oceans and seas are viewed in spectacular cinematography that tracks five whale species—orcas, humpbacks, belugas, narwhals and sperm whales—as they communicate and live with each other.

The series took over three years to film as filmmakers, including National Geographic explorer and photographer Brian Skerry, traveled to 24 locations to learn from the world’s largest marine mammals.

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Executive produced by Weaver’s Avatar and Aliens director James Cameron, the series explores relationships within whale communities, including several firsts such as evidence suggesting beluga whales give themselves names so groups can keep track of each other.

The series also includes the first cross-species adoption to be recorded when a beluga pod adopts a narwhal.

Along with the series, National Geographic is also releasing Skerry’s book Secrets of the Whales, which is on sale April 6 and is currently available for pre-order along with a special May ocean issue of National Geographic Magazine, which is available online at in mid-April.

Secrets of the Whales premieres on Disney+ on Thursday, April 22.

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